How intuitions work

Photo by Richard Kalvar/Magnum When people say such things, they are not typically drawing conclusions from a chain of reasoning. The person who avoids getting in the stranger’s car is not thinking: ‘He displayed these three behavioural cues and, therefore, he poses a risk.’ The email isn’t flagged by going through an explicit checklist. The deal doesn’t announce its flaws through a formal audit.

In each case, something is simply presented as having a certain character: the man as creepy, the email as fraudulent, the deal as suspect. And yet, acting on these intuitions seems not merely excusable but entirely reasonable. If the man really does strike you as creepy, staying out of his car was probably the smart call – even if you can’t say why.

Despite this, ‘vibes’ and ‘intuitions’ are often dismissed both in daily life and in academic enquiry as irrational or merely heuristic devices. And while we cannot always trust such reactions, they are central, indeed indispensable, to our ability to rationally navigate the world. Philosophers, however, have done surprisingly little to illuminate the rational credentials of these ordinary kinds of intuitions.

Instead, they have focused the bulk of their attention on a much more rarefied kind of intuition called rational intuition, which is taken to function primarily in the a priori disciplines of philosophy, logic and mathematics. My objective is to explain why our everyday intuitive reactions can have such rational force. The key is to see that intuition works in much the same way as perception, in that both can directly present something to us as actual.

Once we understand what gives perception this feature, we can see why intuitions might involve exercising the same basic kind of cognitive capacity. A standard way of characterising rational intuition is in terms of seemings, by analogy with perception. Just as it perceptually seems to you that there is a car in the garage, so it can intellectually seem to you that 2 + 2 = 4 – the former presenting a physical fact, the latter a conceptual one.

But rational intuition and the everyday intuition at work when you decline to get in a stranger’s car are not as far apart as this rarefied example suggests: the philosopher’s intuition is, at bottom, a highly specialised version of the same basic capacity. To draw these two capacities together, let’s consider a favourite pastime of philosophers: the thought experiment. Philosophers have a penchant for exotica, which is never more clearly on display than in their invocation of thought experiments.