Topics Science

Question I was very fortunate to be given the opportunity to hear Professor Lipton lecture on the Philosophy of Science at my 6th form recently. He used an allegory to describe scientific progress as a process of elimination, where the chance of finding the truth is increased with every refuted theory and every new paradigm shift. The allegory was that, should you lose your keys in your house, and you know with certainty that they are in one of the rooms, then each room you search and find nothing in can be discounted, leaving you with less rooms to search and a greater likelihood of finding the key. My question is simply: what if there is no key?

Accepted:
June 7, 2007

Comments

This is a good question. I gave the lost keys analogy as part of a reaction to the pessimistic argument that since past scientific theories have turned out to be wrong then its likely that present scientific theories will turn out to be wrong as well. My reaction is that we may be learning from our mistakes and indeed we cannot discover the truth immediately but must try things out and eliminate what turns out to be mistaken. In this case, a history of false theories does not show that present theories are likely to false; indeed it may make it more likely that they are true.

But what if there is no key? Your point I take it is this. Sure, if we know that one of a group of competing theories is correct, and we can rule some of them out, then this will increase the probability that one of the remaining theories is true. But maybe none of the theories we consider is true. In that case, no amount of elimination will expose the truth.

Clearly, if no theory we will every consider is true, then we will never come up with the truth. Moreover, it is not impossible that we are in this depressing situation: we don’t know whether we are or we aren’t. The question then, whether, if that is our situation, we should take the history of false theories as good or bad news. Does it make it more or less likely that we will in fact come up with the truth? The point of the keys analogy is that it may make it more likely, because discovering our mistakes may help to guide us towards the truth. Discovering that things are not a certain way may be a valuable clue to how they are.

So my reaction may be sound even though we don't know in advance that we will think of the truth. But I admit that the situation is not straightforward. For example, someone could counter my suggestion that failures are useful by arguing that a history of failures provides depressing evidence about the power of our minds, namely that we are just not very good at discovering the truth. To deal with this objection, I think one has to give a finer-grained account of scientific theories, not just treat them as completely true or simply false; but that is a long story.