Scepticism

My main philosophical interest for the last 20 years or so has been epistemology, the study of what we can and cannot know, what the limitations on knowledge are. My natural inclination is to be sceptical of claims to knowledge. In my view there are good reasons for suspecting that our confidence in what we think we know is not well founded, and that the greater the confidence someone has in a position the more likely they are to be on very shaky ground.

Recently I have noticed that other fields of study are coming up with work that underwrites the sceptical position. For instance, a few years ago I read 3 books by the biologist Andrew Parker. The books are mainly about vision, and describe his work particularly in the evolution of colour vision. In these volumes he describes in great detail both the seeing end in different versions of the eye, and also the seen end and the physics of the different ways nature has evolved that give us colours to see. (I'm not really happy with the way I've phrased that, but it'll do.) This convinced me that the colours we see are created by the brain - they represent something out there, but we cannot be sure exactly what. Cannot, in the previous sentence, indicates a fundamental barrier to knowledge. Certainly colour does not exist in the accepted sense: it's a creation of our brains.

I have taken an intelligent interest in cosmology, as much as a non-physicist can. One thing we can be reasonably sure of is that there is a whole lot out there we do not understand. There are theoretical reasons for thinking that there must be dark matter, dark energy, but so far we are not able to detect either directly. Gravitational lensing of distant objects makes us think that there must be a massive something between us and it. But we cannot actually detect that something itself. Who knows what else there might be out there, and who knows how accurate our present understanding of the natural world is? But if we have good reasons for suspecting that we are ignorant of something in excess of 90% of what exists, how can we claim to have secure knowledge of the other 10%? All we can say is that what we think we know represents what is actually there well enough to produce effects we can repeat and describe, whether in my toaster, or by flying the Atlantic and sending space-craft to Saturn, or in the Collider at CERN. We can trust what we think we see well enough to support our evolution, but perhaps (necessarily) no better than that.

Then there is all the interesting work going on in Neuroscience and Psychology. There is experimental evidence that seems to show that limb movements which we take to be the result of conscious decisions are in fact initiated in the brain long (up to 6 seconds) before we become aware of them. Miles's TV series shows, among other things, how pre-conscious emotions determine what we take to be rational decisions. Work by psychologists with illusions is also convincing that a good chunk of perception is in the brain, not the sense organs. For example, the subject is shown a face saying either BAH or PAH. The lip movement is clear and distinct. He also hears the speaker's voice saying either BAH or PAH. But the sound played is always BAH. Even the researcher who described this, after 20 years of working on it, always hears what the mouth seems to say, despite the fact that he knows very well what sound is actually reaching the ears. It always works. For some reason the brain hears what the eye sees, not what comes in the ears. There is a lot of work along these lines showing similar things. In other words, our perceptions are, to a larger extent than we would want to think, constructed in our brains, and are not a reliable reflection of the world as it is.

Now the BBC has reported some work with painkillers described in Science Translational Medicine. In short, people acting as experimental subjects are hooked up to a system that delivers a powerful pain killer, and are also subjected to some pain. The experiment seems to show that the subjects' experience of pain is greater or less depending on what they are told is happening, and not on the pain given or the pain killer administered. The brain's expectation of pain can completely wipe out the effect of the pain killer, for example. It's well worth reading the item.

The point is, of course, that our experience of the external world and how it impinges on us is created in the brain, and is not directly connected to our experience itself. What we think is what we experience, not what happens to us.

The idea that we can be certain of anything outside our own heads appears more and more ridiculous.