The Metaphysics of Philosophy, Knowledge and Morality Chapter 6

Chapter 6
Sensory data

If it comes as a surprise that science is as full of holes as Swiss cheese, it is much less of a surprise that our sensory data is flawed. We know that since early childhood.

When we put part of a stick in water, it suddenly appears to be broken, a phenomenon caused by the refraction of light in water. When we touch hot iron, initially it appears to be cold, and by the time we realise it's hot, we already have blisters on our skin at best. Our senses are imperfect. In fact, they are grossly imperfect. They seem to be fine-tuned for survival, rather than for understanding reality as it is.

Our eyes have an instinctive shutter mechanism that kicks in before we know it to save our sight from flying objects. We also have peripheral vision with motion detection to see predators before they stalk us. We smell excrement very acutely, because it's unsafe to eat, but we can't smell poisonous plants or tell who's who by their urine, because that appearently isn't key to our survival. Our hearing is far less sensitive than that of most animals, and our sense of touch is rather blunt unless we're blind. We are well-equipped for the particular natural environment in which we used to live before civilisation, but only with a view to staying alive, and not for purposes of exploring the Universe.

We believe our eyes and hands most, which is why scientific models need to be visual and tangible to make sense to us. Atoms only make sense when they're magnified to human scale, planets only when they're shrunk to hand-size. Then we see what they're all about. Or so we think. The survival factors are hard-wired in our brain, i.e. we are conditioned to believing our senses and to considering their data extremely firm and certain. If we did not do so, we would probably not be around to reflect on our situation.

We sense reality like most mammals, but we're also capable of intellectually criticising what we sense and seek a more profound understanding of the world around us. We're hard-wired to have a very specific - and grossly inaccurate - model of the world, but we can also transcend that level temporarily and pretend that what we see and touch is not necessarily the ultimate reality. We know that an iron ball is just a fluffy cloud of atoms and that colours are actually different wavelengths of reflected light, yet we keep away from swinging iron balls and we gaze at rainbows in awe. We are in turn instinctive and reflective or reflective and instinctive. That's a key part of the human condition.