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Heroes of Science – Episode 12


What we’re interested in is how good the supporting evidence is and how rational it is to believe something.

When we think of Bertrand Russell and his great desire to define something that was rock solid, something that would provide a basis for certain knowledge. He thought that was going to be the case in mathematics, and his work with Whitehead and Principia Mathematica, it was the quest for the logical foundations of mathematics and it was an inquiry known as the logicist programme, and it was shown by Gödel and others not to be feasible.  He abandoned the attempt and turned to philosophy where he thought the epistemological for a basis of certainty, the Cartesian quest, you know, Descartes began the meditations and first philosophy with the enquiry, what can I know that cannot be doubted, and Russell was always very eager to look for that. 

In that respect, Russell stands at something of an angle at the way that we should think of the quest for knowledge because perhaps the quest for knowledge should not be a quest for certainty, for the thing that’s rock solid, but the quest for what is most rational and most rigorously tested in the way of what to think.   This is the big difference, I think, between science and religion again because in the case of religions there are dogmas, there are teachings which have to be accepted as the very basis, the premise for whatever else one thinks and therefore certain is woven into the very fabric of that kind of view.   But in the case of science, science’s quest is always defeasible which means more evidence, better experimentation, sharper reasoning might show that we haven’t got it quite right and that we’ve got to adjust, it may even turn out that some paradigm that we’re working with is flawed and we have to think in terms of a different paradigm, this is what happened with classical physics and ???? physics.  So the idea there is that we are setting ourselves the idea of truth and certainty as the long term objective but we’re not worried if we don’t have it, what we’re interested in is how good the supporting evidence is and how rational it is to believe something.

I’ll give you an example, this is not in any way a fudge, I’ll give you an example.  If you were reading David Hume in the bath last night you probably came across his argument about induction and the way of putting this is to say the fact that the sun has risen every morning in the past millions of years is no guarantee that its going to do it tomorrow, so this is the flaw with induction, or the problem that it poses to us.  So you might say to yourself, OK, even though I’ve got wet every time I’ve been out in the rain without an umbrella, maybe next time I won’t.  You see that it’s pouring outside, you think to yourself, it’s a great opportunity to test the fallibility of inductive inference, so you sally forth into the rain without an umbrella.  So what is a third party going think of you?  He’s going to think you’re an idiot, he’s going to think you’re being very, very irrational.  Why?  Because you’re not proportioning the evidence that you have and the background information that you’ve got to what you act or think.  The very word rationality, ratio, means proportion: proportion of evidence to action and belief. And its rationality, it’s to rational belief that we should be looking for rational ways of looking at and dealing with the world.  Whether its knowledge, whether it’s true, well that’s something that we very much hope to be able to get eventually, but the real test is rationality.  And this is why if it’s not rational to think that there are fairies at the bottom of the garden then it’s not rational to think that there are any supernatural entities in the universe at all.  It’s a question not of knowledge but of reason.