Barcass like this, who gonna bring it to the table? Boss talk, who your girlfriend favorite? Boss talk, we gon' do it how you want it. Boss talk, yeah, everybody on it. Boss talk, it's a unique hustle. Check it, check it, check it. It's a unique hustle, it's your boy, you CEO man, hey man, look out man. Hey, we in the building, man.  This different, man. These guys right here got a serious connection, man. I'ma be real, which I got that boy Bobo in here. I got Mr. Lee in here and he's a Leo is in here. Y'all know what time it is, man. Say, man, we gon' do some talking, man, about sweet Jones, right? Come on. Say, man, P.M.C., man. Pimp. Man, you know, today is his birthday. Yeah, that's good.  You know what I mean? I was a fan. You guys actually had a connection with P.M.C. Yeah. And I thank God that I got to meet all you guys, man. And thank you guys for all the stories, cause I know I pick up the phone and call each and every one of you. And y'all never back down on giving me something to say, hey, man, that's what Pimp represented, man. Oh, really? So thank you guys, man. But how was you when you met P.M.C.? Mm. That was in 93, beginning of 93. She is 60, 80. So let me see, 80, 60, 70, 90, 92. Carried in one, nigga. She about 22? 22? 22, somebody there? A long time ago. 22 years old. And the crazy part about it is when you look at P.M.C., and he was before his time. Wait, wait before his time. You see what I'm saying? Like, I knew before his time when I heard the first track. When I heard, I'm like, what the hell? Well, you know what? You say that, but he was really right on time. Okay, explain. Because at that time, more rappers in Texas were more, well, I ain't gonna say the ones that were out had a little political thing to them.  Then you had Run C. You know what I mean? He was more on the Pimpish type of thing. When UGK came and bought the street element to the game, which it was other rappers out doing it. They came right on time. You know what I mean? It was needed. It was needed. That music was needed at that time, I believe. Wow. God, God don't make mistakes. And so, you can say, I wish I would have done this. I wish I would have done that, but sooner and things like that, but God's got a plan for you at that particular time. And it was right on time. Wow. When you think about P.M.C., you're younger, right? Yeah. So, when you come on the scene, it's later on, right? In what capacity? For as, for as the way, when y'all did the UGK thing, and when the, I see the UGK, Mama West, you know, that was the time when you guys was really do some work together, right at the end, right? Yeah, when he got out in 2005, but I've known Pimpin' Buns since the 80s when we were children. Correct, correct.  And when they did that, it was an explosion. And right now, still to this day, we got the whole motherfucking world on our PA nuts, man. Come on. Got the whole world screaming trill, come on. Yeah, that's something that I seen come from them. I remember talking to you in the parking lot and we was talking about those shirts and I'll never forget it. And my biggest thing owning this store, when Pimpin' first died, he was in this parking lot selling really CDs. He was with us. He was, and I was here and this store was here and basically what tripped me out about it was we still was true to the fact of if it wasn't going to his family, we weren't even entertaining it. Even then, I remember the conversation. Now think about that. I'm weighing a whole different city. Five hours away from home. There's nobody watching me.  Oh yeah, for sure. But I told them how it laid out and if it ain't benefiting, there ain't no need to even. That's exactly what we discussed. And that was years ago. This is when it first had happened. I remember talking to you. I remember talking to Pimpin' Ken. It was certain people that I linked in with cause I'm a fan. I'm like, I want to do this. I had already been selling them Al Jere's t-shirts.  I know you mad at him. He Dan, Dan, I don't even know if you sell him the whole, but anyway. Bring Al Jere's back, man.  But at any rate. It was Texas, man. It was basically, whoo, we liked that. It was a nigga. That was a culture-vulture doll, nigga. Yeah, but dude. He a nigga's fair for it, man. You fair for it, too, because you did. Cause you were trying to get the nigga to rock with you and he wouldn't rock with you.  You seen that Al Jere's ad. I was telling Yeezy this. That had Pimpin' on it. You've never seen that? What? You seen it, right? He had the black shirt on with the black shades. Yeah, yeah, I've seen the shirt. He said, he gave me that particular shirt. Yeah, I had that shirt in here. No, I mean that particular shirt. Yeah. The one that's on there. Wow. He's just going for it. Yeah, that's hard. Yeah, I still got that shirt. Man, so, Mr. Lee, I listened to that whole last project you did. You went and dealt with a lot of niggas on that project, man. Yeah.  This nigga on there? Cause I had to go back and listen to the whole thing. Yeah. How important was it for you to touch that in the right way, you know, as far as knowing that this would be the last project? I mean, for me, it was just closure. Because think about when people pass away like that, a lot of people don't know the conversations that had plans that were being made. I was supposed to work with Pimp when he came back home. Okay. We was going to do an album together. You know what I'm saying? I think it was going to be his last album on Rapaliter, whatever it was. And we were talking. And a lot of strong points I had in my career I was giving to him. And when he passed away, it devastated me. You know what I'm saying? And a lot of things, a lot of albums got done after he died that I didn't have anything to do with it. But when I got the opportunity to do that, it was like me getting closer. I cried many nights working on that album. I felt like he was in that with me too, a couple of times. Listening to them vocals. Yeah. It's wild. They're looking over my shoulder like, man, cut my hair. But it was just more than that for me. It was just getting a closure of it for me. Yeah. I really enjoyed it, man. You had a bunch of people on that thing, man. He met your friend. I think David Bannon was on there. Yeah. Which one was that? Yeah. What was it called? He was on that song. I forgot what the name of the song was. No, I'm talking about the whole, the project was. It was Long Live Pimp. Long Live Pimp. Oh, with the white cover. Yeah. Now I'm going to say this and I'm going to get off it. Now a lot of that stuff, I had to stop listening to it.  Players like myself who got taken off a lot of these monumental songs that people would have seen.   Nigga, our vocals got clean, swept off them hoes and other niggas put on them. By the time it got to me, it wasn't even on there. And I know what you're talking about.  Come on, man. You man. You man. Man, man, man, man. You bought it, though. I got to his bunch of niggas in this bottle. Talk about what? Yeah, yeah, yeah, yeah, yeah. Spent your truth, nigga.  But it was all good. There was some people that was on there? It was, you know, just different people like, hey man, I was on this song. I was on this yada yada. I said, look, bro, I don't, it's not my decision for that. Oh, for sure. You know what I mean? Once we got past, it was all good.  Beto! That's what we're gonna do. Man, yeah. That's my dog. So when you, Mr. Lee, so when you did that, how did you go into preparing who you would put on different tracks? Like you said, I talked to Beto. Okay. His wife had some input in a couple of them in the label and we just put it together. I know for me, like David Bannon was one that I got and it was like two more that I got on there. You know what I'm saying? But it was just a collaboration of that. Juicy J was, Juicy J was on there? Yeah, he was on the project before I got there. Oh, I can't even say I ever heard it. You heard the album? I'm a whole-eyed nigga when it come down to it. Oh, petty.  Yeah, yeah, yeah, yeah. Yeah, because think about it. If we in here right now creating content for boss talk one-on-one, something happens, unfortunately. Somebody else get their hands off it and they sweep everything we did collectively and just replace it. I put it in, I talked about that in my book though. Appreciate it. You know what I'm saying? You know why I talked about it in the book? Because people are here spending their money and their time and their efforts doing a lot of things. And when somebody unexpectedly pass away or get killed, we have sympathy for that family, we should. But that family don't have no mindset to finish the business or let the business go through that that artist had with other people. Yeah, for real. You have people out there spending $20,000 on verses, $15,000, $10,000. And then they get ready to put their records out and the family's putting season to season until they can put it out. We all get out here. Everybody has a mistake, makes this main mistake of getting a feature from an artist. Our producer are gonna be and don't have no paperwork. And when the people pass away, oh my God.  So that's something that I wrote about because I want people to be aware of it.  And if you don't have paperwork in place, these people are not gonna honor the business that they loved ones was involved with. They don't care. There's no loyalty in that. I know a brother out of Dallas. I'm in the streets doing my thing. He actually did big business with him and his project was on its way and Pimp died. But he got that front end. We had the records. We ain't know where it was going. Somebody out of Dallas? Somebody out of Dallas with it, huh? You said somebody out of Dallas? Yeah. You know him too. Oh, me or the Mac? Me or the Mac. Yeah, yeah, yeah, yeah. You know what I mean? Yes, I remember that. He was putting me and said, hey, shout out to Seventeen, boy. Check your medicine, boy. But now, he was putting me and Sevim on this project and shooting at the Dallas. Me, Pimp, and Sevim on a whole underground mixtape for Mel the Mac. We had about four of the songs done. Oh, yeah, I had just left there. Yeah. That's when I left. You remember when we had the Titty and the Bentley? Yeah. And the Bentley was sitting that front? On the highway or at the house? No, when we was leaving the house, we was leaving the high rise going to Port Arthur after we was going to Beaumont for him to report. Okay. And you remember seeing me? I was at the house when the Bentley was, and you had to come get it on the flat bed. Oh, man, that's a whole other story. Yeah, but no, that's the same time. Cause as I was leaving, Mel the Mac was calling me, telling me he was headed down there. Okay. So it was like within a day or two. Right. When I was eating them big old shrimp with the...  And he fell in love with them dolphins, man. Me and them dolphins was looking good. Man, so good. Okay, now, PMC, some of the coldest verses that have ever been laid with PMC, some of the coldest producing ever been done is PMC, man. Yes, sir. So when you go back to, what's one of your ultimate, like one of your favorite verses? Favorite verses. Kick dough. That's the one K-A-L-C. That kick dough, bro. Man, when I first heard that, I said, ooh, ooh, that boy in his element. Yeah. Yeah. That boy was in his element. It's hard to beat that verse on there. That one, and there's, I mean, so many. I don't get mad. No, no, no. I'm gonna go around the room. I'm gonna make you get yours, because I don't want to say one in time. I want you to say mine. The kick dough. Which one do you got?  Okay. 316. Oh, yeah. That's personal, though. True, true, true. Yeah, you can feel everything through that. Oh, my God. So I was there. Come on, it's like you just can be metamorphic into the situation where he was rapping about. You can see it. I was there.  What'd you say when he would come out to move when he'd get through? Because he ain't acting bad. What did you like, damn, if that's what? Oh, you didn't know. You would just sit there in a moment. Well, back then, Pym was just Pym. It was Bun. To see Bun work was a work of art. So he was the one more flashy with the work. Pym was working on his craft as far as rapping back then. By the time Riding Dirty came out, he was sharp, sharp, sharp. But Bun was not really sharp. Yeah. You can see that. Yeah, you can see that. You can see it. You can see it. A lot of people talk about the verse on Murder. Yeah, I hear that a lot. But that last verse Bun did, I left it wet for you. That ain't no punk either.  And he was writing. And when we got back, Pym was like, you done? Because he was out of the booth in the console room. And he was like, yeah, I'm done. He hit that button. Pow! That bass. I got a question for you in a minute. Yeah. Okay, so mine is Pinky Ring. Pinky Ring. You like Pinky Ring. Man, didn't it go rec so hard on that? Oh, yeah. Man. That Pinky Ring went in. And Pym went hard on it. Shout out to Surge. Surge did that beat. Okay. Surge, yo. So you seen them writing process, freestyle and process early, early 90. Early, early. Okay, so what I got to see was early 2000.  Yeah, they could do it. Was that born that back then? Yeah. I told you, we just went around the corner. We ran around the corner. I mean, we went probably down to the freeway and back that distance. Born that he was writing, had started to write. He had, I read it when we came back here I already finished writing, I already busted his ad libs, everything. Done. Damn. Yeah, born a different animal. You see, I taught the born one them kind of do it. One time we came to town, we went around to about four different studios. We went in studio sessions probably 30 minutes, 45 minutes. People have food laid out for them. Now we ain't here for all that. We ain't here for all that. The big deep, we ain't here for all that. We hear the bus. One time he had me roll a blunt.  He said, Bobo, go downstairs and count the money. I go downstairs and count the money. By the time I was coming back in, Bobo was coming out the booth. God damn. Damn it. Just enough for me to count about six grand. Yeah. The back end, that was the back end. Wow, wow. So, he a different animal. Different animal. He a different animal too. After riding dirty, Pimp became that. I think it was a monster. He was a monster.  Yeah. What'd you think out? Yeah, yeah. He would do all that moving around in the booth to where it sound like his voice come from here. I was throwing them out. From here, I'd never seen nobody do it before. Damn. Bitch. Yeah, he do it, man. That's amazing. Yeah, yeah. He doing it himself. He doing it himself. All his back doors, he doing them. Yeah, he got it real.  By the time he got to in his 30s, I think it was an animal. And it shocked, I ain't gonna say it shocked me. I was so happy that when he came out of jail, he still had it. Yeah. I was listening for that. I was like, oh, joy. Did he have this though? Was he able to get in that motherfucking booth without pinning pad and construct that song off the top of his head? Let me tell you something. Let me tell you something. When I first met him, well, one time I met them at the studio after we had already been introduced. And somebody had a, I think Bun, they used to stay in the residence in. Yeah. Out there in Los Colinas. And Bun had a party in his room. A lot of people came. I was in him from Nemesis came, a lot of people. It wasn't just a bad boy. It was a kickback type of thing. A couple of girls. And them boys got the freestyling. Come on. Bro, they freestyle like songs. Exactly. And this was when they were teenagers. And when they finished freestyling, I'll take that back. Let's fret for it. After I moved to Port Arthur, I came to learn that all the freestyling, what they were seeing in the freestyles had actually happened. Damn. The stuff about them kicking in the dough and stealing that album and all that other stuff. Supertype was a different album. Yeah. That we heard. You know, y'all didn't get to hear Wee Wee. Y'all didn't get to hear 93 Mac. Y'all didn't get to hear Menagee Tois. Something like that. Yeah, it's out. It's out on YouTube, but you didn't get to hear it in this full element. Like those songs were about to be big, big, big. At 93 Mac. Well, Mr. Lee, when you look at like to see the supertype go to the ride and dirty, that element of it where you start to see the screw, you know, the screwed and DJ screw and the botany boys come into that element. What did you think about that when you first seen that? Because you love music, so I know you watch it. I mean, I was heavily influenced by it. You see what I'm saying? That's what really triggered me to start the whole thing situation with the screwed up hooks and tracks, you know what I'm saying? I got that from listening to that album. Okay, okay. You know what I mean? So that's, I was heavily influenced by it. I was always influenced by Pimp C with the organs and all of that. That's where it come from. You know, we both come from church. So, you know, me, him, you know, Joe does the same thing too. But you can't hear Mr. Lee track. 90% of my tracks gonna have organs in them. Wow. That's just what it is. That's how I get down, you know what I mean? So all of that influence came from listening to UGK. Wow. And how did you feel like when you seen it go from the supertype to that next album? Cause it changed for me. Oh, big time. It changed, you seen the change. You seen the change. It became way more musical. He backed off of the production a lot. You know, he let N.O. Joe handle some of it, you know. Some of it, he had the ideas. He would make the tracks at home, you know, like murder. He did that beat. He did 360, not 360, what's the one everybody love? Diamonds and Wood. Diamonds and Wood. All that was done. Then he take it to N.O. Joe and N.O. Joe, we do the beat, we do the drums. N.O. Joe had a knack for those drums. Yeah, yeah, yeah. P.L.C. did it too. I mean, the snare pimp used with the clap on it. The drum machine. I mean, come on, man. It was the drum machine. Yeah, yeah, but yeah, that boy went with N.O. Joe to, you know, redo the drums on those beats that he already had, and it made it sound bigger. P.L.C. had to realize during that time that we were living. You wanted your album. People used to measure the album sound against certain projects. Yeah.  It was the Chronic. That Chronic album sound is so big, so, so big that he wanted his beats in the quality. I think the guy named was Bernie Grubman. Bernie Grubman did the mastering. The mastering. The mix that was by Brown. Yeah, see, but he wanted that. We would sit up and have conversations about Bernie Grubman and all these people in California, but here in Texas, we wanted it done here in Texas. So, and he found N.O. Joe. N.O. Joe had that style of pushing the speakers that he wanted. That 808, huh? Huh? Was it 808? The 808 was already, he was already using 808. Pimp had 808. Yeah, he was using that through the R8. Yeah. You know what I'm saying? The stuff you heard on Super Tide and not the, I'm not gonna say through or to Swallow, but the one before that, the Southern Way, that was R8, man. Yeah.  And N.I.G.A. Sake. You heard that N.I.G.A. Drums mine. Yeah. And N.I.G.A. Drums' sound monkey. Yeah. If you got weak drums, he ain't trying to hear it. No, no, and notice how it listens before crooked letters. Yeah. Wow. What do you think? You didn't hear that slug. You didn't hear that slug. I heard this slug. You heard that slug? Yeah. I heard that slug. You saw him now.  The way that everybody still shows him love and do you think he gets the love that he deserves? I think he can get more. Oh, yeah. I think he can get more, but you know what?  You can't. He's an urban legend. Yeah, you can't do that. UGK has a group period, man. You can't, United States, the whole world, you cannot miss them guys. You can't. And you get certain people, outcast, not the group outcast, a person that's an outcast. Correct. You know what I'm saying?   You know what I mean? Let me ask you this. We don't boss talk one on one. Boss talk one on one. We some bosses.    You know what I'm saying?  I'm sitting next to the legend Mr. Lee on the track. Now, he talking about it being influenced by UGK.  Because these are my pills, and this nigga is a pioneer.  So listening to beats that I can't afford at the motherfucking time. Now I'm sitting there hoping, wishing, and praying, I'm about to steal one of these motherfuckers and mix tape this up. This nigga broke the mold with his sound. And look how unbelievable he is, man. You have to give it to who you go to. I mean, you know, the thing about it is a lot of people don't understand the experience of friendship and the brotherhood that you have with people. They look at the exterior part. But you know, you're not a part of them two, three o'clock in the morning phone calls that I was getting from this dude. When we talked about music, where he was one, when I was sampling his voice when he was in jail, right? Because I wanted to pay homage to him and keep his name alive. That's what my purpose was. He knew that when he came out. So you sample pimp and jail, why he's in jail? When he came out, he said, hey man, I appreciate you keeping my name alive.  He said, man, your drums is one of the closest to mine that I've ever heard, man, you know what I'm saying? The boys don't know what to do with your sound, man. The way you swing in the drums and the sabbath swinging in the drums was going the other way that he was that in tune. We was rap, he was, man, we would be on the phone, do it or put the beat on and start rapping on the phone. Come on, man. That's the type of stuff he did. And you know what it is, is the love for what he did. He loved it. And when you able to share that love with other people. That was odd. We don't get that. We don't get that. Now let me say this. He's right about that. Now you got those musical three in the morning conversations. Now me and Bobo got to motherfucking three, four hour of music, isn't that moving? This nigga will wake you up and talk to you into the sun, come on. Yup, he will do that too. That's all it. That's all it. He will. About anything. About everything. Let me ask you about the link with Master P. I gotta bring it up. The Master P, the stuff he did with them. When they came up, I know you know about it, Bobo. I think it was Bobo's. One of them telling me about some kind of way they got in the bathroom and did this music. I think it was. Oh, that was a. They got in to try and sound out. Break a mouse out. That's what he told me. That was at San Jack. Yeah. House on San Jack. Yeah. The room I lived in. I knew you wouldn't know about it. Yeah, it was my room, the bathroom, and then the weed room. Well, the bathroom with the weed room was the studio. Okay. That's the one. I don't know if I'll tell you about how he for this giant, I'm gonna say for this. Yeah, yeah. They gave him what was old in the form of a studio equipment. In the form of a studio equipment. Okay. And once he got all that hooked up, that became a full fledged studio. He had the Big Mackey board, you know, back when it had for us come out. I can't remember how many tracks, 36 tracks. Not even 48 on there. Yeah, yeah, some big ones. All the great mics, the DA88s, you know, all that type of stuff. So that bathroom was one of those old, I mean, it's an old house. You know what I mean? Yeah. Is that house still standing? Yeah. That's a old house. That's kind of hanging a good neighborhood, but that's a, that's a okay area. Yeah, yeah, it is. Cause we used to have to shoot down nine to get to the hood, you know? So yeah, they, that was, it was just acoustically, Pip had this thing that he always talked about. It don't matter what you record. It's what you mix. Huh. Mm. It's all in the mix. So he, he could record in a truck. See, nobody knew, but you know, y'all who was going in and out of there, that it was dead type of capacity of a studio in there. Yes. The rumor was it was just mounds of weed and niggas was hailing and getting highs of motherfuckers. Nah. And one day I went over there, boom, boom, boom, unannounced. You told me about that. Yeah. I went over there unannounced. I'm trying to smoke for free. That nigga something bun out the door to meet me on the porch. He said bun out the door? Yeah. See, I didn't know bun as close as I knew Pimp in the beginning.    You want to hit this? You know what I mean? I hit this. And then they can say, man, Pimp said you got to go. He was like that. So when it was just the, what the distinct memory of, I know P and Pimp them definitely had the ups and downs, run-ins, whatnot. But just how was the chemistry when the music was being made? Business. Straight business. Straight business. Oh yeah, he's one of them guys. I mean, P's an artist.  And shout out Mr. 3-2, I mean them boys. It's only a few people I know that are like true artists in this city. Gunnamese, you know how you can just say Gunnamese, start rapping. It's gonna get hard. Go rap. Go rap. Yeah, and rap whole it. Well, that actually is. Did they? No, I ain't gonna say did they think, because I know, did you think P could rap back then? So who? I thought he was clever with his rhymes. I thought he was better than Silt and Shocker. What about you, Mr. Lee? I heard some of the early rap stuff. Well, well, well, you can't, the Pimp got him after the stuff before that. No, I'm not. I mean, when he first started, you would never think that. He would've been as big. As big as he is, that he was. You wouldn't have thought that that was gonna happen. But that just goes to show you about somebody that's a scholar of something and is willing to learn and perfect. Yes. And that's where he came from mediocre to icon.  He was gonna work. He was gonna work. What about his brother, tell him I rap on beat, did I get back on beat? Nigga, you off beat. You can't rap, nigga. Well, I can't say that Blue Face did it. And he didn't, he's not successful either.  What you mean he not successful? I mean, he's successful, but he's not successful. You can't say that man is successful when you can, you guys looking at success in the wrong way. I'm looking at success as a 20 year run. No, I get it. But the nigga young, you gotta understand Blue Face, a young dude. What song, what song he got?  Okay, he's successful. Am I right?  He's just not consistent, he's just not consistent. He can't rap. I think you got it. You just got it. You never know. He's a reality. I'm gonna be honest with you. When you look at the younger people, I get them different leeway than I do. I can speak my truth about them.  So I can't be real artist. I'm just like real artist, man. No, I might not like it. He said no. I mean, what it is is that, and I think this is why I've been able to do this so long is that I understand that everybody has different strengths. Yes. We can't look at in the eyes of a 90s rapper or a 90s music lover and look at these kids today and expect to see what we saw back then. It doesn't exist. Yes, it don't. But they have different hustles than we had. That's right. And they're reaching way more people than we were back in the day with the streammen. And all of that. So it's an old different ball game, really. But the flip side of that is they are dying in tremendous numbers. They are being locked up. So they are getting way more emotion and traction, but they are risking it all for that motion and that traction. So at the end of the day, having longevity from being a 90s hustler or a rapper or whatever, early 2000s, where would you really wanna be? Would you wanna sacrifice your life for two, three summers of fame? So the dynamics of it is really crazy, man. I gotta go back to Silk the Shocker cause you're on that play from the South Stack Gs, nigga, Silk went in on that.  Silk went in on that, nigga. And Silk been lost. You heard what I just said. Silk ain't out there. He ain't on Mamma Mia. Nah, Silk had his position, though. Yeah, he did. He did. He played it to me. One thing you got to really realize about Silk the Shocker, he never presented himself as an emcee like that. But you know, wait a minute, though. You do know he was the emcee that they built the company around? Yeah. Who? Silk. Silk was. There ain't no way. Yeah, that's who the rapper was supposed to be. Why not Seymour? Seymour wasn't him down there yet. I mean, he hit more people than Seymour did. For real? Yeah. He had the youth, bro. When you get the youth, you got everything, Jack. They had the look. And he had a couple of key features. I mean, he did something with, I think Beyonce and them did. Yeah. What about Mystical? Mystical, too? Mystical was kind of, what? No, I'm talking about for as far as he went to the army. You gotta understand, I'm thinking back of how his, yeah, his personal, just him moving around the way he did. He wasn't just there like that for me. I seen him, he left and he came back. I'm telling you. Mystical was so ahead of his time. He was jamming. That nigga was bad, but I'm just saying, you could tell he left. And I took care of that when I interviewed him. Like, you could tell he left. Like he came back, but he left and then, you know. He had more to talk about? That nigga was bad, man. And that nigga, I put him up there, probably number one, no-limit, that was cold, man. Artist. That nigga used to dance while he rapped. That nigga was a straight performer. Who you got number one, no-limit artist? Mia. I'm going with Mia. Me, too. Okay, Mia. Shit. Mia. I was between the two. Balls lady mama, Mia between the two. You right. Mia the one, Mia was the most consistent rapper You right. You right. I ain't lying. I regress. Sorry, mama Mia. Miss circle was talented. Don't get it twisted, but he was not consistent enough as she was. But, you know, their development came after they had did that with Pimp and their songs in the build up.  You know what I mean? And that was one of the things that kind of, I believe was where, you know, they had the little issues was because of that. Let me tell you something. And I think Mr. Lee, I'm always into, I'm into sports. Yeah. Mainly football. You know what I mean? If Patrick Holmes wouldn't ended up sit with the Miami Dolphins at that time, he wouldn't have been Patrick Holmes. So being in a great situation helped you out. And when he was able to construct Beats by the Pound, that take a lot of weight off your shoulders when you can come with hit songs like that. Now all you gotta do is come with the hooks. Yeah. And the way they was recording, it was a collective effort. I mean, somebody might could say this, oh yeah, put this hook in there. It ain't all about, I got them. And UGK instance, it was just two men doing everything and coming out with albums. When you got eight, nine motherfuckers in the studio collabing on a record. Yeah. And you got, how many producers is in Beats by the Pound four? Yeah. Them boys was jamming. Shout out to my brother, Moby did. Yeah. My brother, man. Yeah. You know, I love KLC back. KLC. KLC a lot. I don't play no game about KLC. KLC a real dude. He makes some real Beats. Yeah. I think Moby Dick was the. Moby had the hooks. He singing, you know what I'm saying? Yeah. Playing that piano, man. Yeah, yeah, yeah.  But you and him was just, you just listened to everything he said, didn't you? Listen to him. Yeah. And talk crazy with him. That's why I say, when I talk to him in my mind, I say, this why this nigga like this nigga, this is crazy. Yeah, we. I be talking about what is going on, man. He was piece of a box. Yeah, we just. We just passionate. Yeah. He was crazy. We just passionate, man. Yeah. And he still on what he stood on. Me and him, we actually got close. I had some stuff like that because I wanted to verse from it. And I had a Mike Moag hit him up. It's like, hey, Mr. Lee, want to get a verse. And Pimp told him to tell me 10,000. So Mike Moag called me and said, yeah. Pimp say 10,000. I said, man, he paying, they didn't even know 10,000 dollars for no verse, man. He crazy. What you talking about? He told Pimp like, well, man, I don't know what we're going to do then.  And we left. We ain't do nothing. So Slim had a song that Pimp was getting on and Pimp had to come to my house to lay it. So when he pulled up and he saw my crib, he was like, damn. So then we, he went in record at the record. We talked. He said, man, I ain't even know you had it like this, man.  I said, man, take my number down. And we started talking almost every other day. Man, I talked about when he was in prison, when he got out of prison, what was going on, all of these stories.   But let me say this. Who was your best marriage with your tracks and the artist? Ooh, I know what I want to hear what you say. My best marriage? Yeah. It's two, bro. I got an X in a current. Can I guess one? Tuck, slim thug. Yup. Thuggle. And then it's nipsy. Wow. That's hard. That's hard. I can't, bro. You know what is kind of crazy for me?  Yeah. Then you got Kiki. Then you got Zero. Then you got Trade.  And it's just like we, he got a good voice. Went back in time, bro. That voice, that voice, bro. But when you create a sound with people like that, and that's what happened, then it's just gonna go like that. I just, I just, because most people, most people would have some kind of fallout and can't reproduce that sound for the fans who really waiting on it, you know? Which I'll able to deliver it. I did that for Switch House, too. It's got consistency. When Switch House had the, when Carnival Beats and Switch House had kind of part ways, I picked up the pieces for them and kept it going. I did it with Do-it-Dot, too. Yeah, come on. You know what I'm saying? Damn. Do-it-Dot, they lost their producer.  Y'all heard that new, y'all heard that slim thug and that Daven on that Dre beat? Yeah. I redid it.  Yeah, it'll go hard. Yeah. I ain't heard it. Slim thug got that voice, man. Yeah, yeah, yeah. He a bad nigga. Bad nigga. The boss. The bad always have been. You know, I always stood out. I listen to them ever since when he went in on All Them Boys when they was into it, when he did a whole, that nigga did a whole West Coast beats diss track. He's my bag in a day, right? They don't really give him the credit he need to have, though. That nigga rap, man. That boy can really rap. See, I got that. Him and Kiki, them the ones. That Kiki's so consistent. Yeah. That nigga can ride a beat better than anybody you ever want to see. That nigga can ride a beat. I give it to them, too, right there. He the one pretty much stamped that sound of that A&B rhyme scheme in that flow. You would have to get that to Kiki. Yeah, you got to. Kiki was the dude. I got to take it back to Pem CD. I think he'll be proud of what's going on in the South right now. He'll be on People Ask. If that boy was on the internet. Hmm. Yeah, we talked about that. A lot of boys would have it, man.  Yeah, that's what I'm about to say.  Nah, it's gonna be.  His mouth was bad, bro. When he speak on you, it was a wrap. You might as well just go ahead and just sit to the side. Yeah, take that.   A lot of people have. Wow. Yeah. Yeah, he gonna talk to you. Okay, if we had the idea what the word could be. Every other day in these days terms, Pimp was going viral every other day. But what would we call it back then? Well, was it really every other day or they just make a scene like that? Cause I think he had way more good times than bad times. He did.  He only did all that. He did a few of it, but I don't think that it was just a consistent thing that he did, but you know what it is? So that man did not bite his tongue though. That was the thing. If he don't say something, he's saying. That wasn't Pimp right there. Because before Pimp, I think Pimp, just my opinion, felt like he missed a lot of time that four years. And he was trying to play catch up and get where he needed to be. Because he could have been there within that four years of him sitting down.  Yeah. I mean, come on, bro. That was a lot of money he missed. Yeah. You know about the movie deal? What movie deal? Ice T as son of a script. He told me about it, I don't know the logistics on it, you know. Ice T wanted him on Law and Order. Send him this script. Worth a couple million dollars.  Why though, Pimp?  I'm sitting there looking at this motherfucker's script like, let me do that motherfucker's action. I never wanted to take, he told me he was gonna go to school and take acting classes. Oh, yeah, David Bannon told him to do that. So he could present himself correct? Yeah. Yeah, he wasn't gonna, I mean, that was a art to him. That's all right, I'm not gonna disrespect their craft by getting out there and saying I can rap. I mean, I can act. Yeah, he wasn't gonna do that in half an hour. Yeah. I think he would eventually slow down on popping up everywhere. He was just trying to get to where he was trying to get and help all his people out at the same time. Man, do people understand how many people he was trying to help at the same damn time? Yes. I was trying to ask you about this, the Three Six Mafia and his link with them and Juicy J and him, like, how did that, it seemed like a hell of a bun. I wasn't there. You see what I'm saying? I just, the way they had the same kind of feel though. Yeah, they did. It seemed so. We thought about the same time. Correct. Yeah, then you know Juicy J, Juicy J, Pimp, me, and maybe, I don't know, maybe a couple of other producers out there, but we used to sample certain things. Yeah. And they sampled the same things. Yes. You know what I'm saying? So that's why his music, it was a perfect marriage. It seemed a bun. You could tell it was a bun. Yeah. I just think about the phases of Pimp C, you know what I mean? I think he met them sometime in, for sure, while he was living in Atlanta. Yeah, for sure. Yeah, for sure. I never met them to the funeral.  You never met him to the funeral. He wasn't tied in with Project Pat? Yeah. Okay. Not like that, but he was a Project Pat fan before he was. He was a Project Pat fan. Oh my God, yeah. That's how the international player record came out. Yeah, already. Yeah, he was a Project Pat fan. That was a Project Pat beat. Yeah, first. Yeah. Yeah, that's the game, man.  On Pimp's birthday, man. Yeah, Pimp's birthday. Speaking of the birthday. Yeah. Let's tell you about this one story. All right, let's go. One time, mama called me. She said, baby, he about to be 23. We got a show in Dallas on his birthday. Let's throw him a party. So I said, okay. No, we was, we weren't rich. You know what I'm saying? We were just a regular old cat. You know, so I was trying to think, hmm, what can I do here in Dallas that I know they gon' like in Port Arthur? Cause a lot of people was coming. So I said, seafood. Easy peasy. Easy peasy, seafood. So I went to Red Lobster. Yes, sir. I went to Red Lobster and I got about $4,500 worth of those cold shrimp with the crab legs and I don't know what we told him. They were in one hotel before the show. We started, mama started laying the hits to him. Hey man, some wrong, something happened to the rooms. We got to switch hotels. Okay. So I got everything. I didn't go, this was the first show that I didn't go to in Dallas or UGK.  Like nigga, where is you?  You know what I'm saying? Cause when he, when they all walked in that conference room, it was like, bo bo! Bro, it was just, and we kicked it and we kicked it and we kicked it all night, bro. On his birthday. 23.  That was like 1997. Yeah man, 1997, 1998, yeah. And just, that was UGK.  And we just ate shrimp, ate crab, kid, I got him a birthday cake. We did everything, bro. We had a celebration.   We had to have Popeye's chicken. Come on. The box of chicken in there was silly.  But the liquor, you know, when you have so many shows back to back to back, unless you just alcoholic, you ain't gonna finish the bottle from the night before. So we got so much crown. You know, that was mama's drink of choice. We had so much crown and, I don't know. Maybe Hennessy, but bro, it was so many bottles in there, we got sloppy. Wow. We got sloppy and we ate good. I know, boy, you remember that day, in the conference room, off of 635, I believe it was at the Sheraton after. Well, man, we had a great, great, great time. So this time, when Pimp came home, the dynamics of Texas rap artists getting great paid for shows. That changed. Was at an all-time low. The highest paid rapper at that time, you couldn't guess who it would be. Probably Lil Flip or... Probably Lil Flip. Paul Wall. Bigger than Lil Flip? Man, Paul Wall was damn near getting 25 racks of show at that time. When Pimp came home, he started seeing what bars was, you know, and he's like, well, what I'm gonna go for? He say if boom, getting such and such, and they want me, I want this. And if they want UGK, what was that number he said that UGK ain't going until they get that number? Let me tell you, it was probably, I remember he was going for about 25 or higher, wasn't it? By itself. By itself. So what did he say he wanted for UGK? UGK had to lease out 50 to 100. 50 racks. Yeah. To do a UGK.  And it wasn't that many UGK shows. And check this out.  He ain't gonna ever get it. He stuck to it. We ain't doing it till it comes. Oh, yeah. It came. It lined up for him, too. It lined up for him. Club Blue played him. That was the first ones grabbed it. Niggas on the Dallas grabbed it whole. We grabbed it. Man. And that was the last show.  Niggas was hanging from the ceiling, man.  I mean, if I get upset with you or you get pissed at me, we men. We're not women. The dynamic between us is bigger than, oh man, you tripping over a girl. Cause that's the only thing it was ever over. You know what I'm saying? Some like, you know, nothing, never over no money. Never over no music. It was always, I don't like, you was late.  Why you not here?  So for anybody to have a dynamic, trying to build a dynamic that they had big, big problems, they didn't. When I went to that time that you saw me at the house on Jimmy Johnson, when I walked into the up, the high rise, I said, Chad, I need to talk to you. Because yeah, they were at odds, you know, but it was the same kind of odds that UGK had always been there, you know. I got my click, you got your click. Yeah, yeah, yeah, yeah. Yeah, he vented sometime, but so what? So what?   It never was nothing like that. And so when I walked into that high rise and I said, nigga, sit down. This how I used to talk to him, sit down, bro.  I don't know, man. And so it was on a Sunday, I can remember. And I got there quite late, probably about six, seven o'clock that night. And he said, and he was just, he let me vent. But man, you need, man, y'all missing all this money. You tripping again, y'all, you need me back down here.  He just, that back when he had the razor. Razor? He hit me with the razor, bam, bam. Show me a picture, him and bud, just that day on stage at the car show right in Houston. Okay. Just that day, I said, so y'all back? He said, yeah, we finna start doing shows. That was in October, the first, the first. So he said, we back good, Bobo. We're back good, Bobo. We finna start making that money. The first show, like you said, was in on Thanksgiving Day, 19, excuse me, 2007. Right? Damn it. Right? Thanksgiving Day. He was talking about coming over to my house, you know, in the lobby. I'm going to stay with Bobo.  If I remember, I think some of the footage of that show was in that get through video. That's a badass hotel. The Magnolia downtown Dallas, right? Remember the icon? Yes. Okay, keep going with your story. So yeah, then two weeks later, he's passed. So what transpired in between him telling me we good, them hugging in the lobby of that hotel at the Magnolia in two weeks you passed. So something happened in two weeks that a girl was out there trying to say that there still was some friction between UGK. Well, there never was no friction. Let me say this clearly. Not no real friction. I know what you're talking about. Everybody who feel like, you know, they had the vision and they had friction.  Yeah, y'all think that. Let me just say this, guys. It's what you got to understand, man. A lot of places where you see people saying this and saying that from a fan perspective, come from a hurt place to be honest with you.  I'm just being real. People hurt, people hurt because you was hurt.  But I would not hurt other people. You know what I mean? I'm not after. Listen, listen, listen. Different people deal with it in different ways. I'm not trying to destroy no legacy. I get that. UGK is an institution. I get that. You know what I'm saying? Niggas is running around doing different things because of the place they at with it mentally. But let me say this. How many brothers you got? How many brothers you got? I got three. How many brothers you got? No. How many brothers you got? Okay, check this out. Me and you.  Some of the best, some of the best. Hard to fight each other on the Z. But it was one of your outside friends tried to side with you.  Cause now you and your brother against that nigga. Yeah, yeah, yeah. So when you know that dynamics, you know that dynamic, you stay out of nigga's business.  Ooh, yeah. And I just be listening. And at the end I say, you're quite mad on you, old boy.  And at the end of the day, I'm not finna get in them niggas business. I agree with that. That's real. I agree with that. And like I said, was it anything ever so serious? Hell no. Nothing was ever so serious at all. Now here's my question. What y'all not gonna do is stop these fans from doing whatever they wanna do to try to create these narratives. This ain't no famous, niggas. This what I need y'all to do. Can y'all ask to them iTunes links, go to them band camps, get them goddamn trio hats.  Y'all wanna support Lord of that Motherfucker super tight TV. I need one of them. Yeah. Hey, but let me ask you this. Yes sir. Okay. Now, I'm from Port Arthur. I know the both of them. That's both my friends. Now, when the whole thing looked like, okay, Bun got his team. Pimp got his team. Yeah. Why I couldn't play on both teams? You could have. You could have. I did. Yeah, you could have. I did. But niggas try to act like, it never was like that though, bro. It was only like, how long was Pimp on? Almost two years. Almost. So he was not on for four, 24 months, right? Uh-uh. Bro. You could have, bro. I did. You could have.   Yeah, the middle fingers. You know all about the middle fingers? I like with both of them though. Yeah, me too.   Yeah, I mean, all UGK ruckus. I'll rock Peter Vicious, man. Yeah, I'll rock Peter Vicious.  I'll rock Peter Vicious. I'll repeat, man. Yeah, man. Boy, y'all gonna make me cry, lad. Now, I forgot what you asked me. Yeah, yeah, man, so. But he did a little pimp, boy. And he did what y'all do, man. Yeah, I do.  Trying to start a pot, bro. You're quite mad, don't you? No, I'm happy. It's SuperTight TV. Y'all tune in and subscribe. Because I'm gonna boss talk one-on-one. Thank God, man. I'm gonna boss talk one-on-one with a boss this time. Man.  I love to get, I know the chemistry, man.  Like I said, a lot of times, coming from a fan perspective, again, looking at real friends who link with pimp, man, I gotta respect it, man. Just for y'all to even come over here, I appreciate y'all. Man, I dropped a whole pimp-sea tribute song, man. You did. Coming out today, man, a little later, man.  Come on.  Yeah, he did. I'm gonna be, it's on YouTube? Nah, I'm gonna drop it later today. It's called Still Gripping. Send it to me.  I stay away from that because nigga be, oh, you trying to sound like pimp.  But this song, nigga, I embody the pimp. You gon' hear it. Okay. All ready, man. So, do I leave anything out? Do we leave anything out? Happy birthday to the pimp. Happy birthday to the pimp. Happy birthday to the pimp. See, man, free young pimp. Long little pimp, man. Like I said, I ain't real. You came for life. For life, man, and shout out to Bun B, man. Yeah, Trill Burger's coming soon. Man, Trill Burger's coming soon. I ain't had one that year. See, I ain't had one either. I don't care. I don't care. I need one that year. I'll give mine when I give it. When you get it. Yeah. Man, you understand? It's spot-posed to be in Houston. On Shepherd? Yes, it is. I believe it was. In February. In February. I will be in the campus. You know I'm going down there. Yeah, see, we gon' go. We all supported, man. I'm very proud of Bun, man. How y'all think Bun doing since, you know, that was a big loss for him? It's hard, man.   And then, you know what I mean? I know, I was there at the funeral for him. I seen when that boy walked up to that casket. Oh, wait, what?  You talking about Pimp? Pimp and Bun? He was in that room? Part of his motherfucking soul left his body in there. You the first person that was about that. I seen that. My own eyes, Jack. Bun was... He don't want to broke now. He was destroyed, my nigga. Bun broke down at the funeral, bro. Yeah, I was there. I mean, at that viewing portion of the film. Yeah. What did you think when you seen his body? You don't remember that? What did you think when you saw his body? Oh, yeah. I saw Pimp body? It wasn't the Pimp that I knew, man. Yeah. He stayed out to it, bro. Swollen up and everything for him like that. Shit wasn't...  Yeah, mine too, bro. It broke my heart because I was supposed to meet that man the day he got back. I talked to him before he flew out to LA. Wow.  He switched up his time and I was actually supposed to fly to LA and meet him and David Bannon. When you hear the story about David Bannon saying that Pimp called him and he ain't answer the phone on that song that we did. Yeah, I was supposed to meet him. I got the call, bro, that day that I was packing my stuff up, getting ready to go out there. Come on, man. Dang.  I collapsed in my closet and I cried like a baby, bro. Wow. He affected so many people. What was you when you heard about it? I'm gonna ask you that. I lived in Lancaster. And then they told you you couldn't believe it. No, I was driving back in that month. I had a real entry garage with Ali behind the house. I was driving out and this chick I knew called me. I think her name was Christian and I picked up that phone and she said what she had to say and I was like, because if everybody remember, it was about a month or two before that a false rumor came up like that. And everybody was like, I'm thinking it's another one of those false rumors. And I'm standing back and up and then I start hitting down the alley. Now they kind of swerve, curve around like that. And that curve, well, headed to that curve, mama picks up the phone. She didn't say hello. Hey, baby, nothing. She just said these words. He gone. Yeah, baby, he gone. Wow.  And just like he said, I parked my car. I didn't, I mean, I parked the truck I was driving in that little curve before I could get to the street and just broke down. Wow. What was you at? We had just left eights time. We did all them recordings, was at the high rise. So I'm back in PA moving around doing business. When I got the call, I was two streets from my house and I was next to a graveyard. To my left at the light on 25th street, I was next to a graveyard and my homeboy Mr. Three Com and he say, sorry to hear about your brother. I'm thinking he talking about one of my brothers. And he said, man, Pimp died.  Same words she told him when she picked up the phone, she said, baby, he gone. The street I was on leads you straight to her house if you make like one or two turns. I floored it there. And when I got to the house and walked in, she grabbed me and just cried, man.  And I just held her there for damn near. I can't even tell you for a very long time. It was just them two for a long time, bro. Wow. For a long time. A lot of people didn't see that. I mean, that dynamic. Yeah, she stay strong outside. Oh my God. I was there when mama first became the role manager. We had a different role manager at first. And yeah, I was there when she first did her first show with us and the first two years of her, I was there. And so yeah, they grew together, man. And I mean, she used to have a vending machine business. Yeah. And Chad used to help out with the vending machines. How would Pimp be today? If he was 33 when he passed. And this is what he told you. What in nine? I'm a year older than him. Wow. Man, make sure you guys like and subscribe to the channel, man. Boss talk one on one, man. We want to say happy birthday to PMC, man. Thank these guys, Mr. Lee. He's a Leo Bobo in the building, man. Hey, man, it's been another great segment. Couple of shout outs show. What's up, man? Caught you a big jack, man. What's up, what's up, what's up, man?   They're going to take over. Thank you, guys. I love you all, bro. Thank you. I got one word. I got one phrase that y'all need to remember.  Just remember that. Man. Check it, man. It's been another great segment of Boss Talk 101 when the bosses talk. Yup. Yup.


Hello and welcome back to Beyond Networks, the evolution of living systems. Today, we're finally gonna move back to biology from our excursion into perspectivism and process philosophy. But before we do that, let me just quickly recap. It's been quite a dense and loaded module so far. In lecture one, we refocused our attention away from what we know to what we don't know, from facts, the questions, which are extremely important for scientific inquiry. In lecture two, we asked why it is so hard to think about processes. It's ingrained that we think about the world in terms of things. And we took a very short tour of the history of process philosophy and introduced a few tools for identifying and classifying processes. In lecture three, we looked at the process of scientific inquiry itself. And the main point I wanted to get across there, it's quite complicated, but it's really, really cool, is that our scientific theories evolve quite like other complex adaptive systems, like organisms or technological systems in the way that they adapt to reality, just like an organism adapts to its environment. And that they also share some features with organisms and other adaptive systems, complex adaptive systems.  And we finished that lecture by saying that progress in science requires different strategies at different times, depending on whether you're in a phase of normal science, when you exploit an existing paradigm or revolutionary science, when you explore new perspectives. And I think we are at one of these points where the existing paradigms have exhausted themselves a little bit and it's time to explore and try new perspectives. So in this spirit, we'll move on and look at biology, taking various process perspectives and explore those in a speculative playful manner. So let's get started. I want to start this lecture by reminding you how the majority of Western philosophy and therefore also the foundation of science is based on a substance-based view of the universe. So the main question in this sort of view is what is the world made of? You try to decompose the world and then to identify what the components are of that. And then what these components do is sort of an epiphenomenon, something secondary or derived that depends on the properties of the things. This view has been the mainstream view of philosophers in the Western world since before. Socrates, the pre-Socratic philosophers, just like Parmenides, Democritus or Leukipus. The atomists were focusing on this sort of question, what is the world made of in the case of Democritus and Leukipus, of course? It was made of atoms that sort of bump into each other and cause the phenomena that we see. And so this is sort of manifested by this mechanistic worldview that modern science has adopted that goes back to René Descartes that sees the universe as a sort of an intricate mechanism. And if we take the components of this mechanism apart, we will understand how the world works. So this sort of metaphors based on machines and mechanisms are very, very prevalent. And I'm gonna use the work of contemporary philosopher Dan Nicholson, who is at the Conrad Lorenz Institute here in close to Neuburg at the moment. I'm gonna lean a lot on his work in this area. And I'm gonna quote a contribution he's made to an absolutely fantastic book called Everything Flows. I'm gonna share a link where you can get it for free. It's about processional approaches to biology. And Dan says, but out of the endless array of metaphors used in science, it is difficult to think of one that has been more dominant and has exerted a greater influence than the machine metaphor, which provided the basic theoretical foundation for a mechanistic natural philosophy in both physics and biology. And if you look at a history of science, this idea originally came from physics, but ironically, physics has moved on while biology is firmly stuck in it. So let's look at that in a second. But first of all, let's sort of think what is the consequence of this sort of world we want is that we view the world as deterministic in some, they're strong and weak forms of this. The strong form is Laplacian, the demon that sort of knows where all the parts are and how to interact and then can predict the entire future and the past of the universe. A weaker form is just to say that every effect must have a cause in some way, which is something that we can probably subscribe to. The other aspect of this mechanistic worldview is reductionism, right? So that we approach the world basically by taking it apart. If we want to understand the system, we take it apart, we try to find its parts just like a clockwork, the gears inside. And if we know how those gears interact, then we know how the system works. So as I said, in physics, about 100 years ago, physics moved away from this sort of optimistic view where you have small things that bang into each other. There's a great book by James Laderman and Don Ross, which is called Everything Must Go. And they look at physics in particular and sort of the basic fundamental reality of particle physics and all that. And they say, okay, since relativity, since quantum physics has come, physics has switched from this idea that there's atoms that bump into each other and create all the phenomena to a view that's much more based on sort of fields. Here we have the enterprise, or is it Voyager? I don't know, in some sort of warp field, waves and forces to mix the sci-fi metaphors a bit here. So physics is sort of thinking in a much more systems level way. Fields are, what arrange, so the spatial temporal arrangement of forces that cause the components of the system to sort of organize in a sort of a global way. So think of them in any field. They're little iron shavings and they all align in a certain way. So there's sort of a global patterning generator there. And we rarely think about such mechanisms or such large scale phenomenon in biology. So ironically, while the mechanistic world we came originally from physics, it is much more prevalent in biology today. And this is a little funny. But I mean, so the idea that biology is purely mechanistic starts right with René Descartes as well. So he writes in two different books about the organism. And so one of the quotes here is the human body that's about us is indistinguishable from a perfectly designed automaton. Even we, our bodies at least, because of course he believed that the mind is in a different sort of realm, are purely sort of clockwork mechanisms. Later he writes description of this automaton amounts to an explanation of the organism. So for him, all living systems were purely mechanical systems. And we've already encountered the sort of perfect manifestation of this metaphor of the machine in de la maitrie and is long machine where he writes an organism is basically just a self winding clock. Of course, there's a lot resting on this sort of self winding aspect of the system. And he never tells us exactly how that is supposed to work. And so this machine metaphor, not just for the world in general, for the movement of the planets, but also for the workings, the inner workings of living beings has stayed with us, although it has mutated over time, depending on the most popular technologies of the day. So in the late 18th and early 19th century, the metaphor du jour was the steam engine, no longer the self finding clock. Later on, human bodies became chemical factories in the early 20th century. And nowadays of course we prefer metaphors to come from computer technology. So it's always the sort of the latest, most fashionable technology that provides the metaphors. And it's evolving in parallel with the technology. So what happened at the same time at the conceptual level is sort of stated here by evolutionary biologist, Richard Lewontin, who says the metaphor of all modern science, the machine model that we owe to the cart has ceased to be a metaphor and has become unquestioned reality. Organisms are no longer like machines, they are machines now. Okay, so we've forgotten, and this is the danger with metaphors, we've forgotten that we have adopted terms from or analogies from our technology to talk about natural systems. And so this leads to a bunch of very predominant sort of paradigms that are no longer valid. So we'll talk about those for the rest of the course. Let me just quickly introduce them right here. So one of the phenomena that I'll criticize here is the idea that evolution leads to organisms that are somehow designed, optimized by evolution, by selection, okay? So this idea that evolution is an optimizing process comes of course from computer science and engineering where you optimize the performance of machines as I started saying in the introductory lectures, also optimizing our schedules, our time, our performance. And the other sort of aspect of that is the idea of genetic information and the genetic program in the genome that sort of runs and creates the phenotype as it goes along. These are machine-based, computer-based metaphors. Also very famous of course is the idea that the cell is some sort of factory that's based on molecular machines. This idea of a molecular machine goes back as far as I know to Sydney Brenner. And so he thought about protein and protein complexes, little machines that work in a factory assembly line built the cell. And this has been taken to its culmination in the BioBricks Synthetic Biology Project where the idea is that you create a sort of collection of plasmids that encode different circuit elements. And just like you can build an electronic circuit from basic elements, you could build regulatory circuits in synthetic regulatory circuits and cells by putting together these different plasmids that form the basic elements of those circuits. This project is spectacularly failing right now. In very few cases is it true that these elements are put together and they do what they're supposed to do. We'll talk about why that is later on in the course. And so here we're clearly sort of hitting a wall, hitting the limitations of this engineering metaphor of the machine. And so I'm gonna quote a physicist, David Bohm, with a diagnosis of what's going on in biology. And he says, and why it's so strange, right? He says, modern molecular biologists, okay? He's writing this in the 70s, but things haven't changed very much. Modern molecular biologists generally believe that the whole of life and mind can ultimately be understood in more or less mechanical terms. Thus, we arrive at the very odd result that in the study of life and mind, which are just the fields in which formative cause acting in undivided and unbroken flowing movement is most evident to experience and observation. There is now the strongest belief in the fragmentary animistic approach to reality in biology, no longer in physics. And he thinks, as a physicist, he thinks that's weird. Let's contemplate this again for a second. So the study of life and mind, just the fields in which formative cause, we'll talk about what a formative cause is, acting in undivided and unbroken flowing movement is beautiful, is most evident to experience and observation.  That's how living systems are different from mechanical ones. And especially it's weird that exactly in this area of investigation, we have such a strong belief in the fragmentary animistic approach to reality. There is a disconnect between what we see in biology and how we go about studying. And I've chosen a physicist to tell you that, but of course, there's also a lot of biologists who have noticed this. So basically, this whole mechanistic view of the world comes from substance-based philosophy that underlies Western science and Western philosophy. And the main problem this creates in biology is that you have explanations in terms of things, and then you need to attribute agency to those things. So let's talk about elementary particles and physics or genes as determinants of heredity, form, physiology and behavior in biology. The genes have to do stuff. And it's sort of, the main problem here lies in explaining how they do it.  And there were headlines saying, we found the gay gene here.  It's absurd, okay?  So the idea was that if you would have a genetic explanation for being gay, there would be less pressure in sort of trying to explain that it's a natural thing. That's fair enough.  So there is no connection, causal connection between the two things. The gene produces a protein, that's it. And that's all it does. And so there is a huge gap in trying to explain how a gene is supposed to act to make you behave in a different way, of course. And I'm drawing, this is oversimplified, of course. We are much more sophisticated nowadays, but the problem has sort of remained the same. So we nowadays, we no longer have single genes that cause complex phenotypes, but we have gene regulatory networks. So this is an example, beautiful work by Eric Davidson and his collaborators over 30 years, 40 years of very hard work. They have pieced together a network of those genes that are involved in the determination of the endomysoderm in early sea urchin development. And what you can see here is a diagram. So the names and this diagram are different genes and the arrows show you how these genes are connected in different tissues at different times indicated by color, sort of boxes in the background. Massively complicated, a lot of work, very much detail. Everything has been decomposition. This is the mechanism that creates pattern in this embryo. But the problem is it doesn't really explain how the pattern is formed because it's just a diagram. It's a summary diagram of a lot of work, but the problem here is it doesn't tell you what this system does, right? So in a way, it still has this explanatory gap. It's a thing, it's a static diagram and we need to know how we get from this thing to its behavior and that's the big challenge. In a way, this is not an explanation. It's a challenge. This is wonderful work, but it doesn't explain how the sea urchin grows. It is sort of a challenge for us to sit down and figure out what this system actually does, but it doesn't do this by itself. So if we take a process perspective on biology, we want to know how things work, what they do. This is a problem because a lot of systems biology is not really systems biology. It's the type of systems biology where you go to a meeting, you have a bunch of shapes connected by lines thrown at you and everybody is really impressed, mainly because these diagrams show you, A, it's complicated, B, this person has done a lot of work in their lab. Fantastic, and we're all impressed, but we shouldn't be asking, so how do we get from those diagrams the actual behavior? I think there's two problems. One I've already mentioned, the diagram doesn't tell you what the system actually does and the other one is that these diagrams are not just summary of work, they're also idealizations that sort of distort and also ignore a lot of what's going on underneath and we'll come back to that, of course, during the course. So how can we move beyond this sort of systems biology of the networks? And also by moving beyond networks, networks are an engineering metaphor based on the machine view of the world. How can we move towards a more organic processional view of biology? So several people have tried, there's a long tradition. Aristotle himself was very much influenced by biology, it wasn't called biology at the time, but he was very much interested in animals and their natural history. But I think so the main sort of philosophy modern in modern times here that connects to biology is probably Alfred North Whitehead's philosophy of the organism. He builds on earlier work by Henri Bergson and other people, but basically what he's saying, what he's trying to say with this is that in a way, biology is more important than physics because he denies that there's a distinction between organic and inorganic matter. He goes very far in this. So he becomes a pan-psychist where he believes that even simple matters are in some way sanctioned. We don't have to follow down that path, but the other remarks that he's making are very interesting. He says, biology in a lot of ways is more fundamental than physics because physics is just looking at those aspects of the natural world that are not organic. They're not influenced by this matter. There's no distinction between matter that is organic and inorganic. And he sort of says physics is just explaining that part of the world, which is not a wide, which is less than the world in total, which is living and non-living things. So also he has this sort of idea that through perceiving you become part of the world, you're being in the world and you experience causality directly. So he moves away very much from earlier arguments where or contemporary arguments in philosophy where people were focusing on how we represent the world by language. He says, this is not the case. There's a much more direct way of perceiving the world, just like Michael Polanyi will later say, that you build up a sort of a tacit understanding and awareness of your circumstances.  And there is no sort of disconnect between the world in itself and your representation. So very interesting sort of aspects. I highly recommend you read Science in the Modern World if you're interested in this. We will not have time to go much into his ideas, but so Whitehead is at the beginning of a long tradition of process philosophy moving into biology and this tradition is carried on by one of his students, Suzanne Langer, who is mainly famous as a philosopher of art, but she in the 1950s and 60s also developed what she calls a process-oriented philosophy of biology, which is very interesting. And she says, living systems are composed of acts and by acts she means temporally drawn out living processes. She said, it doesn't make sense to organize, to analyze organisms in terms of what they are made of, their composition, but the acts that constitute them, these processes that work together, an organism is built up by its own acts, she says. Remember, these are processes and these processes should be examined in terms of their temporal structure. We're gonna go a lot into what that means with a temporal structure is in later lectures. Okay, so these are the beginnings of philosophers moving into biology, but here we're gonna focus on the work of biologists who took an explicitly process-based perspective. And one of the important people, of course, at the beginning of that tradition is Conrad Howe Waddington, who in 1957 wrote his fabulous and famous book, Strategy of the Genes, still as accurate and important as it was ever. And he introduced and promoted, mainly in that book, of course, his metaphor, his image of the epigenetic landscape that you can see here in an unusual artistic depiction. So I want to show you that it's actually moving during development and evolution, it's constantly changing its shape. His work, Waddington's work was later formalized by French mathematician, René Tom, who invented a whole branch of mathematics called catastrophe theory to formalize that the ideas that Waddington had in his landscape metaphor. And that work in turn inspired Salvador Dali, who here, this is his last painting that he ever painted. It's called Swallow's Tale, and he depicts one of Tom's mathematical structures in this painting. So this is a formal science of processes and biology and we'll introduce this and talk about it. We'll take a little bit and see what we can still get out of this today. Or take the work of Stuart Kaufman, who in the late 60s starts to model the dynamics of chain regulatory network and also their evolutionary dynamics, how order emerges from random behavior in those networks. Beautiful work that we'll talk about. And most dear to me, the tradition of process structuralism in biology, Waddington's students, Brian Goodwin, was the most prominent figure in this movement. He was my master supervisor, but also other people who would not directly identify themselves as process structuralists like George Oster and Perra Albert, who worked in the tradition of Ivo Divo, took a very similar approach to study the evolution of developmental processes, very much based explicitly on the fact that we're dealing with processes. So we're gonna go into the work of those people and many, many, many more that followed them over the course of this lecture series. But before we can get to the sort of nitty-gritty practicalities, we need to ask ourselves a very fundamental question. I've been throwing this term system around a lot. And it's sort of at the basis of systems biology, what is a system? We'll ask ourselves this question in the next module and also how you can understand systems with the tools of using mathematical models. This will be the topic of the next module. I hope you tune in again next week when we talk about systems and models. Thank you very much for listening. Enjoy the rest of your Sunday. Bye-bye.


In this lecture, we will talk about the thermodynamic scale of temperature and finally, derive an expression for the efficiency of the Corno engine ok. We start by illustrating the Corno cycle on a PV diagram like this, although we used a slightly different illustration earlier, you may recall that you know we used an illustration like this to show more reversible adiabats and isotherms you know we sort of show it schematically in this in this manner. So, each one of the blue line is a reversible isotherm and the red lines are all reversible adiabats. So, Corno engine will operate between 2 reversible adiabats and 2 reversible isotherms. For instance, we may have a Corno engine that starts here and then goes along this let us say goes up to there and then comes down like this maybe like this and then maybe like this. So, this would be a Corno cycle operating between the isotherms T A and T B and these 2 reversible adiabats. Now, what we want to show here is the following. The efficiency of the Corno engine when it operates in a cycle is 1 minus Q C over Q H and we want to show that this depends only on the reservoir temperatures ok. So, we demonstrated in the following manner. So, we take this cycle some amount of heat Q H is supplied during this cycle and some amount of heat Q C is rejected during this cycle. Now, you can easily imagine operating a Corno cycle which is just shifted between these 2 reversible adiabats, but between the same 2 isotherms ok. So, in that case the Corno cycle would look something like this and notice that there will be no difference between this Corno cycle and this Corno cycle. The heat that is supplied will still be Q H and the heat that is rejected will still be Q C. So, I can move it as long as I maintain the spacing between the 2 reversible adiabats I can move this cycle slide this cycle along this isotherm and the amount of heat supplied and the amount of heat rejected will remain the same only the state points will change. On the other hand, if I actually try to move the cycle slide the cycle vertically down let us see what happens if I slide the cycle vertically down. So, I do something like this. Now, you can easily see that this cycle will be different from the original one in terms of heat interaction because now the heat supplied is Q C. What was the heat rejected in the previous cycle is now the heat supplied and you should remember that Q C is less than Q H. Now, this will reject a different amount of heat Q C prime which would be less than Q C. As we slide down the reversible adiabat and go from one isotherm to another the heat interaction decreases. So, Q H is greater than Q C which is greater than Q C prime. So, you can see that the cycles are different now whereas, if I slide along a reversible isotherm cycle remains the same. The heat interaction remains the same only the state points change but when I slide down the reversible adiabat from one isotherm to another the heat interaction changes which tells me that the heat interaction or 1 minus Q C over Q H is a function only of the reservoir temperature. So, only when I slide down the reversible adiabat from one reversible isotherm to another the heat interaction and other things in the cycle change. So, this tells me that the efficiency of the cycle is dependent only on the reservoir temperatures. So, it makes it clear that it is dependent only on the reservoir temperatures. So, Q C over Q H the efficiency itself is a function psi some unknown function psi of the reservoir temperature T H and T C. So, Q C over Q H may be written as some unknown function phi of T H comma T C that is a most important point. So, you know that the ratio of Q C over Q H is a function only of the reservoir temperatures. In fact, even if you look at the cycle you can see that there is nothing else that the efficiency can depend on the only the reservoir temperatures are available for us to adjust. So, it should be clear that the efficiency will depend only on the reservoir temperatures, but this illustration brings it out even more clearly. Now, how do we make use of this information? So, here is what we do. I have engine 1 and which operates between reservoirs T A and T C. So, T A is greater than T C. So, there is also an intermediate reservoir. So, let us write it like this. So, T A is the hot reservoir, T C is a cold reservoir. Engine 1 operates between T A and T C. It is given an amount of heat Q H 1 from the hot reservoir and it produces an amount of work equal to W 1. Now, I construct another device which is composed of two reversible engines 2 and 3. So, this is the device that I am constructing. So, I can enclose this as a new device. So, that consists of two reversible engines. Engine 2 receives the same amount of heat from the high temperature reservoir as engine 1 and produces certain amount of work. It rejects an amount of heat Q C 2 to this reservoir at an intermediate temperature T B. Engine 3 picks up Q H 3 from this reservoir and then rejects an amount of heat Q C 3 to the cold reservoir at T C. So, I have added one more intermediate reservoir and these two reverse engines operate between these two reservoirs.  So, Q C 1 over Q H 1 is a function only of the reservoirs that this engine operates between which is T A and T C. Q C 2 is again a function only of the two reservoirs between which engine 2 operates and those are A and B and Q C 3 similarly is a function only of T B and T C. Now, notice that Q H 2 and Q H 1 are equal. So, Q H 2 and Q H 1 are equal. So, let us just erase this for now. So, Q H 2 and Q H 1 are equal because otherwise the comparison would be unfair. So, we need to give the same amount of heat to the two engines from the same reservoir. Only then the comparison is fair. So, Q H 2 equal to Q H 1. Q C 3 is equal to Q C 1. Let us see why this is Q C 3 which is this one here is equal to Q C 1. Why does this have to be true? Because if Q C 1 is different from Q C 3 then the efficiencies of the two engines will be different. They are both given the same amount of heat from this reservoir and if the amount of heat rejected to this reservoir is different then efficiency of one engine will be different from the efficiency of the other engine. And we have already established that the efficiency of all reversible engines operating between the same reservoirs is the same. So, for that reason and since Q H 1 is equal to Q H 2, Q C 1 must be equal to Q C 3. So, that is what we have written here. And Q H 3 equal to Q C 2. So, Q H 3 is equal to Q C 2. This is because we want this reservoir to operate in a cycle. Remember we want the entire device to operate in a cycle. If during each cycle we reject a certain amount of heat to this reservoir and we pick up a different amount of heat from the reservoir then this reservoir will not actually operate in a cycle. So, how much ever we reject to the reservoir is what we should actually pick up from this reservoir during each cycle. So, if the amount of heat rejected and the amount of heat supplied by the reservoir remains the same and so the reservoir operates in a cycle. So, for that reason we insist that these two should be equal to each other. So, with these constraints I can write the following Q C 1 over Q H 1 may be written as the product of these two quantities. So, this is dependent only on T A and T C, this is dependent only on T B and T C and this ratio is dependent only on T A and T B. Now, this relationship can be satisfied if and only if this function phi unknown function phi is of this form X C of T C divided by X C of T H where X C is again as yet unknown function. So, this is also an unknown function, but now the functional form or functional dependence of the reservoir temperature becomes clear. So, it has to be something like this X C of T C divided by X C of T H. Of course, you must bear in mind that Q C is less than Q H. That means, as the reservoir temperature decreases the heat interaction also decreases provided we are travelling between the same two reversible adiabats provided we are sliding down between the same two reversible adiabats. So, as the reservoir temperature decreases the heat interaction also decreases. So, we have put X C of T C in the numerator X C of T H in the denominator to satisfy this constraint because you may also write this as X C of T H divided by X C of T C and this relationship will still be satisfied, but that would not be consistent with what we just outlined that the heat interaction decreases with decreasing reservoir temperature. So, this is the correct form. There are many, many functions which will satisfy this sort of a relationship. Lord Kelvin initially proposed X C of T to be e raised to T and T could then vary from minus infinity to plus infinity. Supposedly, he did not feel that this was aesthetic. It did not like the fact that temperature could be negative. He did not want temperatures to be negative in this scale. So, he discarded e raised to T and he came up with the even more simple form which is simply that X C of T is equal to T and he said that in this scale the temperatures will go from 0 to infinity. They will not be negative, they will go from 0 to infinity. Now, this scale of temperature has come to be known as the Kelvin absolute or the thermodynamic scale of temperatures. So, X C of T is equal to T which means that Q C over Q H may then be written as T C over T H. So, Q C over Q H may then be written as T C over T H. The only issue that is left unresolved is it is ok to have a new scale like this and then insist that the temperature in this scale should go from 0 to infinity. But how do we relate the values to existing scales? So, by this by the time this was proposed there are already Fahrenheit and centigrade scales. You know that in the centigrade scale water freezes at 0 degree Celsius or water boils at 100 degree Celsius at one atmosphere. So, that is a specific number. How do we come up with the number for this for temperatures in this scale? This means we have to relate the Kelvin scale to the other scales in order to come up with the number. Now, here also the ingenuity of Kelvin comes to the fore. Let us just quickly go back and refresh our memory about what we said about gas thermometers.  So, you may recall that we discussed this in some detail. So, let us just quickly refresh this. So, there is a bulb which contains a bulb which contains a certain amount of gas up to the level of the mercury. So, initially we fill the bulb with some gas say O2 and measure the pressure by adjusting this sliding scale.  We again take the reading we keep doing this for smaller and smaller amounts of gas. Then we change from O2 to N2, repeat the readings again. Maybe go to a third gas helium or neon and repeat the same experiment and measure the pressure. Now, so now let us see what these readings look like. If you plot the readings on a pressure versus time scale, so this could be for instance O2, this could be N2, this could be say neon. And each one of this dot corresponds to a different amount of mass in the bulb. So, we have different amounts of gas in the bulb. So, each one of these readings refers to that. Note that pressure here is proportional to temperature because it is an ideal gas and PV is equal to m times R times T. And it is a constant volume thermometer. So, V is a constant. So, as I reduce my m, the temperature of the reservoir whose temperature and the reservoir whose temperature is to be measured, that temperature remains constant. So, T remains constant. So, you can see that as I keep going down, the as I keep reducing the mass, the pressure value keeps going down. And what was interesting about this plot is the following. These are very, very accurate temperature measurements using constant volume gas thermometer. As we mentioned earlier, constant volume gas thermometer probably comes closest to being a thermometer whose readings are independent of the working substance, meaning O2, N2 or neon. Still they must behave as an ideal gas, but it is probably the most accurate thermometer that can be fabricated. What was interesting about this was that, all these readings for a particular gas fall on a straight line. And if the straight lines corresponding to different gases are all extended up to the x-axis, which is the temperature axis, they all intersect at the same point. And that is at a temperature of minus 273.15 degree Celsius. Of course, this corresponds to zero pressure because the y-axis is on the, because pressure is on the y-axis. So, they all seem to intersect at minus 273.15 at zero pressure. So, Lord Kelvin then asserted that minus 273.15 was the lowest possible temperature that can be achieved. In fact, he said that this is the lowest possible temperature in the entire universe minus 273.15 degree Celsius. Even in the outermost space where we have a high degree of vacuum, he said this is the lowest temperature that can be achieved. Because this corresponded to P equal to zero, the thinking was that outer space, once you go far beyond, it is as close to being absolute vacuum as possible. So, this must be the lowest possible temperature that can be achieved. So, he then asserted that a temperature of zero Kelvin corresponds to minus 273.15 degree Celsius. What is that? There was no evidence at all for any of these assertions. It was just probably an educated guess based on whatever was known at that time. And the interesting aspect is that this assertion that zero Kelvin corresponds to this has withstood the test of time. That is probably what is most remarkable. So, what comes out of the analysis is a new temperature scale and also a connection between the new temperature scale namely the Kelvin scale and the existing scales that zero Kelvin corresponds to minus 273.15 degree Celsius. So, the efficiency of the Carnot engine may now be written as 1 minus Tc over Th. Of course, a temperature of zero Kelvin is not attainable because if you can attain zero Kelvin, then the efficiency of the Carnot engine will be 100 percent, which would be in violation of the Kelvin-Planck statement. The lowest temperature that has been realized so far is 500 pico Kelvin by a team of scientists from MIT. Now, so in order to have an efficiency of 100 percent, we require a temperature of zero Kelvin or we require a reservoir at a low cold reservoir at a temperature of zero Kelvin. Now, let us just go back to the illustration of the Carnot engine that we had. So, here we have a Carnot engine. Now, let us look at process 23. Process 23 is reversible adiabatic expansion when the cylinder has been taken from the high temperature reservoir and kept on this insulated stand and it continues to expand until the temperature reaches Tc, as we said before. So, the expansion continues until it reaches the temperature of the cold reservoir. Now, let us say that the cold reservoir temperature is zero Kelvin. So, this 23 as we can imagine for a temperature in order, in order for this process to reach a temperature of zero Kelvin, you can easily imagine that it will keep going like this and eventually it will asymptote and it will never be able to reach a temperature of zero Kelvin. Number one, number two, for it to actually reach a temperature of zero Kelvin, the cylinder length must be infinite. Cylinder has to be infinitely long for you to actually expand this until it reaches a temperature of zero Kelvin, both of which are not feasible. So, this shows this argument that I am giving here is actually put forth by Peter Atkins and it is a very interesting argument or a very different way to look at this. That both these things suggest that attaining a temperature of zero Kelvin is not possible. So, in the same manner, we can write for a refrigerator, a corner refrigerator, the COP being 1 over Th over Tc minus 1 and for a Carnot heat pump, we may write the COP like this. So, we may finally answer the question that we posed earlier, what is the maximum possible efficiency of a direct engine or maximum possible COP of a reverse engine. Now, we can actually give some numbers. Let us say that we have thermal power plant, which uses the Rankin cycle, let us say operating between high temperature of 1200 Kelvin and rejecting heat to the ambient at 300 Kelvin. Now, I can plug in these values, these temperatures into this expression and then see that the efficiency of such a power plant cannot be more than 75 percent. So, Kelvin Planck statement said that the efficiency of such a plant cannot be 100 percent. So, we were then speculating whether it could be 95, 90, 85, 80 and so on. Now, it turns out that it can only be 75 and modern power plants which use for example, something like an ultra supercritical cycle, which is a variant of the basic Rankin cycle are able to attain efficiencies between 55 and 60 percent. So, you can see that the efficiencies of actual existing power plants have come quite close to the corner efficiency itself. So, now, we can finally calculate a number. So, if you tell me what the reservoir temperatures are, then we can actually calculate the efficiency. In the same manner, let us say that we have a domestic refrigerator that is operating between minus 10 degrees Celsius and the ambient at 30 degrees Celsius. You can see that the COP of this refrigerator cannot be more than 6.575. Clausius statement says the COP cannot be infinity, but now we can see how what the real numbers are like. So, real number is even for a Carnot engine which itself is a theoretical construct can only be 6.575. So, that is what I alluded to in the beginning of our discussion on second law. Not only will second law tell you what it cannot be, it will also tell you what it can be. So, now, you appreciate the difference between the two. Kelvin Planck statement says that it cannot be 100 percent. Clausius statement says it cannot be infinity. Now, based on our discussion of the Carnot engine, we now know what it can be. For example, in this case, the efficiency of the direct engine is 75 percent, efficiency of this refrigerator is 6.575, which are far from 100 percent and infinity. So, second law answers both these questions very nicely. That is probably one of the most important and fundamental contributions of second law to the field of mechanical engineering and indeed thermodynamics. Now, there are some interesting aspects of the Carnot engine, even though it is a theoretical construct. What is that? The efficiency of a Carnot engine. So, this is the efficiency of any engine. This expression holds for any engine that operates in a cycle. This expression holds only for a Carnot engine. Now, if you look at this expression, notice that it depends only on the reservoir temperatures and does not depend on the nature of the working substance. The working substance inside can be anything. As long as it is a pure substance, we should be alright. So, it can be anything. So, the efficiency of the Carnot engine depends only on the reservoir temperatures and not on the nature of the working substance. Which means that if I actually run a Carnot engine, let us say, let us go back to this illustration. So, let us say that we run a Carnot engine between two reservoirs. Let us say that the temperature of this reservoir is not known. But the temperature of the cold reservoir is known. So, Tc is known, Th is not known. That is the temperature that we wish to measure. So, we measure the amount of heat in principle. We measure the amount of heat that is supplied to the engine. We can determine the work that the engine produces as it executes a cyclic process and then determine the efficiency of the engine. So, basically what we are doing is, we are operating the Carnot engine between two reservoirs, one whose temperature is not known, other one whose temperature is known. So, we measure Qh and by measuring the work that the engine puts out per cycle, we know Qc. So, we know the efficiency of the engine. Now, we know one of these temperatures. So, the other temperature can be evaluated. And the value that we get is independent of the working substance. So, the Carnot engine actually is the only thermometer which can actually give readings which are independent of the working substance, at least in principle. At least in principle. That is very, very important to know.