Friday 13 March 2020

What is science? Part 1


There are a number of ways to study philosophy of science. One of the best ways is to read the works of famous philosophers of sciences such as Karl Popper, Thomas Kuhn and Imre Lakatos. Any introductory text on the subject will describe their thought and reading their books will probably tell you more about philosophy of science than I can. But there is no purpose in repeating the words of great men. These people didn’t spend their lives repeating what others had said. If they had they would have remained mediocre thinkers. So, I propose to mention these people only in passing and I will make no references to their books not least because I haven’t read them in many years.

Instead I propose to try to get to the essence of the subject. What is science? In what way can philosophy look at science? I will begin at the beginning and continue until I have nothing more to say.

Modern philosophy begins with scepticism. The first week of an undergraduate philosophy course frequently reduces everyone to the point whereby they accept that they know nothing. This of course takes us back to Socrates. Socrates only knows that he knows nothing. So too Descartes, knows only that he thinks and that he is. The task of philosophy is to rebuild after this initial act of destruction. We are trapped in our own thoughts. We know only these thoughts. We don’t know if the sun will rise tomorrow, nor if there is even an external world with other minds in it. If we can’t even know these things how on earth can we have knowledge about science?

Someone once said that scepticism is like a medieval castle. We cannot storm the keep, but nor can those trapped in the castle sally forth to attack us. It can therefore safely be left in our rear. The sceptic’s argument is very good indeed, but it is not productive. Where do you go with your absolute doubt about almost everything? How do you live your life, believing neither that there is an external world nor other minds?

But how do we get out of the sceptic’s castle? How do we overcome doubt? We do so by means of a leap? Call it a leap of faith if you wish. We make an assumption.

We may not be able to prove philosophically that there is an external world, but we assume that there is one. We may not be able to use logic or reason to demonstrate decisively that other people exist, but we assume that they do. Remaining in the sceptic’s castle is dull, futile and tedious. You will find that you cannot prove that the sun will rise tomorrow. All the truths of science will be beyond your reach because you cannot even begin to make experiments until you make an assumption that the future will be like the past and your eyes don’t deceive you.

This is perhaps the most important lesson for scientists and for scientific truth. It depends on assumptions. We cannot even begin to do science if we remain sceptics about basic facts. Perhaps indeed I am merely a brain in a vat and some mad scientist is feeding my brain with stimuli that make it appear that I inhabit the world that I do. I cannot absolutely refute this, but I cannot begin to do anything if I continue to think that it might be true.

But it is important that scientists and indeed everyone else realises that in order to begin our investigation of truth we have to start with an unjustified assumption. We have to make a leap of faith. Explanations come to an end somewhere as Wittgenstein said and then I am inclined to say: “This is simply what I do.”

Have you ever been questioned by a child about something? To every answer the child may reply “Why?” This can continue for a while, but eventually we will all be stumped. We just say that is how it is. We can give no further reasons. We assume.

The assumptions are hidden, but they are there none the less. They are hidden, because they are so fundamental and so obvious. We assume that scientific experiments are valid because we assume that we can make accurate observations of the world, that our senses are accurate and that most scientists write the truth. We assume that the future will be like the past and that whatever laws of physics have been discovered will continue to apply.

But imagine that the universe is expanding and contracting. At some point let us assume the universe was the size of a tennis ball and then for whatever reason there was a big bang and it started expanding. Well let’s imagine at some point it will contract. It could be today, it could be tomorrow. If it contracted, then the laws of physics that we know at present might suddenly cease to apply. How do I know that this won’t happen tomorrow? After all I can find no reason for why this big bag occurred when it did (if there was indeed a when), rather than a million years later. How can we know when the big contraction might occur?

But to worry about that would make science pointless, so I assume that the universe will not suddenly contract tomorrow. But having pointed out that science depends on assumption it is worth also making scientists realise that they perhaps ought not to be quite so arrogant about the truths they discover. There are scientists who appear to think that they have discovered everything, that they are like Alexander with no more worlds to conquer. But everything they have discovered depended on assumptions and ultimately it all depends on a leap of faith that cannot be proved. Scientists may dismiss this, but they shouldn’t firstly because the dismissal displays merely their ignorance and secondly because they are not alone.

Other forms of knowledge also depend on assumptions and leaps of faith. We assume that our memory of what we did yesterday is reasonably accurate. I cannot prove what I did in private on a particular day last month, but I assume that what I remember reflects reality. Not every truth is repeatable. I cannot repeat the fact that I had sardines for lunch two weeks ago. There is no experiment that can be repeated to demonstrate that truth. So, we allow truths that cannot be repeated by experiment. We assume that memories are accurate without being able to scientifically prove it. There are other truths beyond scientific truths.

Going further back, we assume that people who wrote about the past were not simply lying and that written sources of history give us knowledge about the past. But we cannot repeat the Battle of Hastings like an experiment. We only have what various people wrote about it. Sometimes we may doubt one source about the Battle of Hastings because it contradicts all the other sources, but if we doubted all the sources, we wouldn’t have any history at all. But this depends on an assumption. We assume that people who wrote about past events were not trying to deceive us. We assume that if large numbers of sources describe events in similar ways this gives us evidence. We say that for instance it is beyond a reasonable doubt that the Normans won the Battle of Hastings.

We may not be able to absolutely prove that I eat sardines two weeks ago or that King Harald was killed at the Battle of Hastings. Perhaps he was merely captured and the Normans for political reasons pretended he was killed. But we treat historical events like a trial. We cannot usually absolutely prove anything when someone is on trial. Perhaps all the witnesses were mistaken. Perhaps an unlucky set of circumstantial evidence convicts the wrong man. We know that in law mistakes have been made in the past and will continue to be made in the future. But we allow a standard of proof that is different from formal logic or mathematics. We allow the balance of probabilities. We allow something called proof beyond a reasonable doubt. Absolute scepticism is an unreasonable doubt. That is why the sceptic’s castle is left behind.

The same goes for science. We don’t allow unreasonable doubts to overturn the results of experiments or to overthrow theories that have worked for years. But the lesson from this is that not all truth is scientific, because most events cannot be repeated. We do not live in a laboratory under controlled conditions, but this does not mean that there is no truth outside the laboratory.

There are different standards of truth. There are the truths of mathematics and logic. 2 + 2 = 4.  NOT (p AND NOT p), All bachelors are unmarried etc.  It’s hard even to imagine that these could be false.  It’s perfectly possible to imagine however that I dropped a ball and it went up. Imagine for instance that I’m on a space station. But even the truths of logic depend on assumptions. They assume that there is nothing higher than human logic. They assume that there is no perspective beyond our means of understanding that can view logic differently. This may seem unlikely, but apparently there are more dimensions than three. There are things that science describes that are beyond our imaginations. I cannot imagine 13 dimensions. The words mean nothing. I likewise cannot imagine how 2 + 2 might not equal 4. But who is to say that hundreds of years from now some clever mathematician might explain that in 13 dimensional worlds the laws of arithmetic do not apply? Perhaps they can do so now. Perhaps parallel lines meet in some possible universe even if it involves a contradiction in my logic that they do.  

All truth depends on assumption and we apply a different standard when judging the truths of mathematics, science, personal memory, history and trials. It doesn’t mean that one sort of truth is better or worse than another. There is no point attempting to apply the standards of arithmetic to history. Some of the things that we are most sure about we cannot prove scientifically. How would you go about proving that your big toe itches? Yet you are sure of it. More sure indeed than the fact that Harald got an arrow in his eye in 1066 or that the latest science is correct in every respect. Truths that are assessed in different ways do not rank from most likely to least likely. It does not follow that we believe most firmly in the truths of mathematics, then in the truths of science, then in history then in personal experience. We apply different standards to different truths. But all truth depends on assumption. Theology too depends on an assumption, that is arrived at by a leap of faith. There is a God. This is no worse, nor indeed any different from any other truth.