Megan Craig

Strategic Director , Joom

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What does quantum physics mean for our understanding of our world and our place in it?

Quantum physics now clearly shows a range of seemingly bizarre things to be true: that the same particle can be in many different places at the same time, that things change when we observe them, that particles can be entangled and act the same even though they're millions of miles apart.

All of this challenges our assumptions about how our world works - namely that there is an observable set of events that happens independently of us in the role of the 'experimenter'. Does this imply an action of creation in the act of choosing/observing? Is there no such thing as unbiased observation that doesn't set up an observer effect? And if we are indeed creating our world, what does that say about our ideas about God and religion?

  • Jun 12 2011: I think it was Paul Davies in "The MInd of God" on the new physics who explored what he called the "strong anthropic principle".

    Specifically the question asked was, based on the findings of quantum physics, could it be that the universe was formed all those billions of years ago because we observers now exist billions of years later and are observing it. This sounds counter-intuitive like much in quantum physics. And the idea that an action in the future can in some way influence past events that gave rise to the conditions needed for those future actions to occur sounds bizzare - except for one thing.

    Experimental physicists have conducted experiments showing this can happen in the famous dual slit experiment.

    In it when no measurement is made to determine which slit photons passes through, an interference pattern builds up on th target. But if an observer observes photons passing thru the experiment and knows which slit they passes thru, then the interference pattern ceases to occur. Each photon stops acting like a wave and instead acts like a particle. Just becasue we observed it! This happens even if the observation happens after it passes the barrier / slits. Not only does the experiment "know" its being observed and behave accordingly, it does so even if the observation occurs afterwards not before!

    And Richard Feynman's work shows how quantum interactions can (I must be careful how I express this) work both forwards and backwards in time. Clearly the universe is not how we perceive it.

    I suppose JBS Haldane said it best "The universe is not only queerer than we suppose, it is queerer than we can suppose."

    Perhaps in answer to your question about God I should end with another quote from Haldane. When asked what conclusions he could draw about God and religion from his studies, reflecting on the number of insect species, he said it was clear to him only that God had an inordinate fondness for beetles
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      Jun 12 2011: Wonderful answer, thank you. I'm bowled over by Mr Davies' suggestion, which as you say is perfectly supported by the double-slit experiment. I know I'm going to spend a great deal of time thinking about that in the weeks to come.

      Something about your sentence, "...the universe is not as we perceive it" draws me in. I suppose because again we so easily step back into this paradigm that the universe is or isn't a particular way, and that it's possible for us to objectively perceive that. Whereas of course other versions of this statement are now seeming more compelling and likely, such as for example, "...the universe is *because* we perceive it". The really interesting questions become things like, who are we really, what does it mean to perceive, and what influences that?

      Thanks also for mentioning that first quote - I've loved it for years but have wrongly thought it was by Carl Sagan, since I heard him use it on his show. Good to know where it properly comes from!
  • Jun 30 2011: If a universe comes into existence and no one observes it, does it exist? Is time nothing more than observable change?
  • Jun 12 2011: Further to my other post, by chance here is an excellent article on this subject by Dr Kako in his blog. Here however he talks about the "weak" anthropic principle which implies that this universe was formed and was finely tuned to support life more or less by chance - there are perhaps an infinite number fo other universes that can no support life. But since they cannot suppport life it is reasonable that we exist in the only universe that can.


    There is a whole discussion about variations on the anthropic principle here

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    Jun 10 2011: Hugh Everett thought his interpretation of quantum physics proved immortality:


    What do you think?
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      Jun 10 2011: Hah! That's terrific, thanks for the link. If I was being cheeky though, I'd say the immortality theory only holds up if we accept the convention that time flows forward, which may or may not be the case ;)
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        Jun 11 2011: I gotta keep reading this and the "Time" threads. This is really fascinating. With Hubble we are looking at what happened quite some time ago. Maybe someday man can put something together