Evidence: What Evidence?

You probably are aware of ‘Likes’  on places such as Facebook, Twitter and Instagram. These ‘Likes’ are put into an algorithm and then advertisements come up due to what you apparently ‘Like’.  I love to confuse and add in random ‘Likes’, bell-ringing, star-gazing, flower arranging, shoe repairing etc. My favourite response was from a computer scientist on an Open University programme about computers and statistics. He said that when he bought a book online a recommendation would come up telling him: ‘People like you like the following books…..’ To which he said to camera, ‘I don’t like people like me’!

My mother used to tell me that one day they will tell you that Salmonella is good for you. They will produce statistics to prove it. They will say that this is scientific proof. But statistics are not scientific proof. Statistics are mathematical proofs.

Statistics measure the correlation between two events. How likely they are to occur together. Statistics tries to remove confounding variables; things that also happen at the same time, but are not really correlated. But they do not prove cause and effect.

Science is interested in cause and effect. It is not empirical, another mistake made by non-scientists. Empiricism does not measure cause and effect.

Science measures the link between cause and effect. It does this by experiment. That is why most other disciplines are not scientific. They call themselves scientific (Social Sciences, rather than Sociology, for example) but they cannot do the experiment to test the theory. They can only do the stats.

Example A: If you want to prove that ‘watching violent television makes children violent’, you would need to

  • take two groups of children 24 hours a day, 7 days a week and
  • put those two groups of children in exactly the same environments (food, clothes, rooms, etc) and
  • let one group watch violent TV programmes and
  • not let other group watch violent TV programmes
  • for a number of days/weeks and
  • see if there is a difference in behaviour afterwards.

This experiment would never be allowed, it is unethical; so you cannot do the experiment to prove the link. You can do the stats on children that watch violent TV, but you cannot be sure other things have not had the effect.

Example B: If you want to say that the ‘killing of Archduke Ferdinand in Sarajevo started the First World War‘ you would have to

  1. travel back in time to Sarajevo 1914 and
  2. ‘un-shoot’ Archduke Ferdinand and
  3. see if the First World War still happened.

Good luck getting the grant for that research!

A number of academic disciplines that say they are using scientific methodology are not doing so and a number that say they are using statistics are still not doing scientific methodology.

The example I give my students are two excellent papers by very good teams.

  • one paper says that feeding babies on breast milk makes them more intelligent and
  • one paper says that feeding babies on breast milk doesn’t make them more intelligent.

How do they  find opposite results? By statistical analysis. There is no experimental proof to either claim. There are a lot of confounding variables which get in the way of the correlation between milk and intelligence.

All the scientific evidence points to Salmonella not being good for you, so whatever the stats say, please don’t try the Salmonella.


Cancer and Blame



Most of us probably want to believe that we get what we deserve! However, we were not really put on this earth to make these judgements. We cannot tell how other people really live, what they face each day, and what they deserve let alone blame them for all that happens to them.

A lot of money has been spent on bad science, pseudo science and bad public health. Most epidemiology looks backwards, what has happened, and from that tries to predict what will happen. But we don’t have a crystal ball and no event reoccurs in human populations exactly the same way twice. Yes, we can learn from history, but we cannot copy it or predict how things will turn out in the future. Hence economic prophecies based on pseudo scientific principles. What a lot of twaddle we hear from economists.

Public health initiatives are often based on very poor ideas. You read those ridiculous articles such as eating salt increases your chance of heart attack. The chance they are talking about is usually very small and the amount of salt that had to be consumed to increase this small chance was very, very large. But then a public health official will spend a lot of your money on an anti-salt campaign.

You cannot live without salt. All of your reactions in your body (your metabolism) occur in a salty liquid, a plasma-type substance,  which exists both within the cell and between the cells of your body. You are about 80% water and a lot of salt. You are salty. Your kidneys filter water and salt keeping them in balance to meet your body’s needs. In fact where water goes so does salt. One cannot travel without the other. It is to do with osmotic pressure, keeping your cells at the correct salt-water balance. Too much water (i.e. too little salt) and your cells would swell up and burst. Too little water (i.e. too much salt) and your cells will shrivel and die. It is in balance. There can be too much or too little of everything. Life needs a balance. So campaigns that reduce salt too much also do you harm. If you live in a hot country where you sweat to cool yourself down (too much heat in your body kills you) then you are losing water AND salt. You need to replace BOTH.

A lot of bad science and pseudo science has been done on cancer. Why? Because it gets funding is the simple answer. Unfortunately, if you put in a proposal about cancer (or include education as an outcome!) you tend to stand a better chance of funding. While basic research, the science of cancer cells for example, is needed, a whole load of others get funding on the back of this. So we get the poor results and the silly links between things that aren’t linked at all.

I can invent some silly links myself such as ‘watching tv after 6pm gives you cancer’ or ‘reading gossip magazines gives you cancer’. I can prove these while sitting in my armchair. I would bet that nearly everybody that has died of cancer has watched TV after 6pm. There may be a few exceptions, but they would be brushed aside as exceptions. As to the gossip magazine, if you haven’t read one, you still probably read some gossip in a newspaper or heard it on the radio or TV or from a neighbour so I could still justify my arbitary claim somehow. This is because correlation does not prove causation.

Correlation is when two things occur together. The best example I was given to explain this was by a psychologist colleague. This is it:

In summer more people eat ice cream than in winter

In summer more people drown than in winter

Therefore (stupid correlation bit) eating ice cream causes you to drown.

No it doesn’t. More people eat ice cream in summer because they are hot and it may cool them down. More people swim in summer also to cool them down rather than go swimming when it is freezing outside. You could say that cooling down causes you to drown, but you don’t tend to drown from eating ice cream or sweating, which also cools you down. To drown you need to be trying to swim. In water or another liquid. If more people swim in summer than in winter than there are increased numbers of people at risk of not being able to swim in the water they are in and therefore drowning. We could probably argue that fewer people are watching TV in the summer as they are out doors swimming so watching TV prevents you from drowning. I guess it does as most of us don’t watch it while swimming (or even bathing in our bathrooms, although I have stayed in an hotel with a TV in the bathroom). Still, I would not say that watching TV prevents people from drowning. Now I hope you see that two things may occur together, ice cream eating and swimming, but they don’t necessarily cause the effect, drowning. Swimming doesn’t cause drowning either, if you think about it. It is the inability to swim at that moment in time that may cause you to drown. That may be due to a number of reasons: your general inability to swim, sudden changes in conditions, freak accidents.

Most of the bad pseudo science you hear is this sort of statistical analysis of populations done by people that say they are doing science, but they aren’t.

Well you must have heard a lot about cancer if you are over 20 years old. The most obvious one is ‘smoking causes cancer, particularly lung cancer’. I have a colleague who has never smoked or lived with smokers or lived in smoking areas and died of lung cancer. That would be impossible if smoking causes lung cancer. It increases your risk of getting lung cancer. The problem is that we are very bad at thinking about risk. Risk is to do with probability and we humans are not good at that, hence so many of us gamble. I hear people say that they make a living out of gambling. The only people that really make a living at gambling are the bookies and betting shops, the people behind the counter, not the people in front of it. We all have a flutter. But the flutter has been calculated so that we generally lose. The bookies are better at probability than we are.

Richard Doyle is the epidemiologist that came up with the link between smoking and cancer. He was good at his job. What he also said, that people have chosen to ignore is that if you give up smoking by the age of 30 you will, within about 10 years, have lungs as if you have never smoked. All those campaigns wasting money on getting teenagers to quit. It is the older (parents) that need to quit, the 30+ year olds. All that wasted money because they did not read the rest of the article!

How many of you have been asked by the doctor if you have ever smoked and if you were to say yes, 25 years ago, they would write you down as a smoker and blame all your problems on that. My father gave up smoking 40 years before he died. Still, any pulmonary (lung) condition he had they tried to blame on his having smoked. I would think that being a ‘Bevan Boy’ (sent down the coal mines) in World War 2 at a young age would have been more detrimental to his pulmonary health. Living 40 years after smoking and not having lung cancer may have been a bit of a give away in diagnostic terms; but why go with intelligence when you can go with poor science? There is a lot of stupid on the planet and wow, am I fed up of hearing it.

Coal tar has a detrimental effect on genes. It has carcinogenic chemicals, ones that can alter genetic material, ie cause mutations. That is what a mutation is. A change in one letter in your genetic code. You have three billion letters so finding a change in one of them is a tad difficult. Coupled to that you have 10 trillion cells. Each cell has that 3 billion letter dictionary. So you are looking for one letter change amongst 3 billion x 10 trillion. That is a one in a 30 billion, trillion letter. Now do you see the problem?

When daft pseudo-gerontologists (I have one in mind) come up with ways to live longer, which basically boil down to the need to diagnose people earlier  with any disease potential (and we all have that) so they can live longer they aren’t really gerontologists. They aren’t biologists. They are popularists. They are talking for the sake of hearing their own voices. Where do you look? Which one of the 10 trillion cells? Which one of the 3 billion letters in one of those cells? Do you think people haven’t been trying to diagnose cancer before it kills you? Not just treat it, but spot it as early as possible?

We have always known that diagnosing cancer is problematic. By the time we can see it there needs to be about a gram of cells. A gram is a very small amount. A teaspoon of sugar (which may ‘help the medicine go down’!) has about 5 grams on it. A gram of cells contains about a billion cells. That’s a lot of cells. Cancerous cells.

The problem with bad science is the lack of understanding of the biology of us.

Cancer has two things going on; one is genetic, the other is cell growth. The genetic bit is that there needs to be a mutation and they occur randomly. A mutation can hit a gene that has no effect on cancerous growth. But it can hit a gene that does. However, one gene in one cell won’t kill you. What you need is for the cell to grow and grow.

Most cells only grow, make new cells, to replace old cells that have worn out and died. Most of your bodily activities are carried out by ‘terminally differentiated cells’ functional end cells which do not grow and make new cells. For instance oxygen is carried in your blood by red blood cells (erythrocytes). They are terminally differentiated. They have completed their growth and development and have become restricted in what they can do (differentiated). They can only be red blood cells. When they get worn out they get replaced by cells further back in development, growing cells that are quite undeveloped. They form pools of new cells that then go on to differentiate (become different) and highly specialised, such as red blood cells that only really carry out one function, carry oxygen in the blood. It is a bit like any manufacturing process. You take a sheet of metal, It could be made into anything. If is made into the front driver side of a car door. It does not then become a car roof.

The early, underdeveloped cells that provide later cells are the Stem Cells.

If you have a mutation in a cell that is about to become a red blood cell (a reticulocyte) it may not have much effect. Some red blood cells may lack a certain protein (genes code for proteins). If the mutation is in a gene for the protein that carries oxygen (haemoglobin) then there is a problem, the red cell is inefficient. If it is in a gene for cell growth it has no effect as red cells don’t grow. To get a cancer in blood cell you need to affect the cells that grow, the stem cells. There are not many of them and they are hard to find. Why would you look for them unless you already knew there was a blood cancer?

So predicting cancer and finding cancer is very difficult. If it was easy those pseudo-scientists could do it too.

Cristian Tomasetti and cancer geneticist Bert Vogelstein of Johns Hopkins School of Medicine have just released results showing that it is bad luck getting cancer, a matter of random chance. Which gene and which cell is not predictable.

Some cancers are more common than others. Cancers occur more often in tissues that are replaced often such as the linings of tubes (stomach tubes, gut tubes, urinary tubes) and the linings of us, our skin. These are from epithelial tissues and the cancers they give rise to are called carcinomas.

Cells involved in support and transport are also replaced due to wear and tear. Each time a cell is replaced it may cause a mutation to be made in its genetic material ( a misreading of the code). Tissue such as blood, bone, cartilage and dermal tissue is replaced often. This sort of tissue, connective tissue can therefore become cancerous causing cancers called sarcomas.

Cells that seldom grow and divide, muscle and nerves, seldom pass on mistakes so muscle and neural cancers are very rare. The neural tissue that supports nerve cells, glial tissue, does grow and that can become cancerous. Any tissue that grows is thus vulnerable. Tissue that doesn’t grow is less vulnerable. That’s it. Most of the other populist stuff about cancer is not worth the funding or the TV time. Hopefully this latest finding, which is what we all knew anyway, will stop some of the dreadful nonsense and false hope. Even more importantly, it may stop the blame.