If, as philosophers say, the world is nothing like how humans perceive it to be, what is it really like?

 

 

You raise a perennially fascinating question; one where philosophy, science and the observable facts all come into play.
Obviously the perception of the world of humans or any other species cannot be wholly valid and reliable – simply because that perception is both caused and limited by our bodily apparatus. Scientists assure us that there are ranges of colours and levels of sound that we cannot detect. They exist independently of our ability to perceive them. We cannot detect a still body of invisible gas; but it exists – to the extent that in certain circumstances it may even kill us. This is simply the way we have evolved; greater sensitivity would provide no survival advantage, but would carry with it some corollary drawback.
Given that the existence of such undetectable phenomena is part of what the world is "really like", the world is different from how we are able to perceive and experience it. Therefore what we can perceive is not the reality of what exists but a representation; just as a photograph or a tape-recording is a representation of what it has preserved and not the real entity.
Descartes, in anti-empiricist mode, provided a clear insight into this. He argued that direct observation is often deceptive; we can never be truly confident that phenomena really are as they appear. Claude Monet is said to have been heavily influenced by this when he produced his famous paintings of Rouen cathedral in different conditions of light, radically changing their appearance – but not, of course, the reality of the cathedral. Paradoxically, experiments examining the validity of eye-witness accounts always seem to support Descartes on this.
Even more crucially, Kant pointed out that our senses have certain vital but limited functions: our eyes can see; our ears can hear, and so on. But they cannot do anything else (how could they; why should they?). Thus the sum of what we can perceive is the sum of what we can comprehend. However that does not mean that what we cannot perceive cannot possibly exist; on the contrary, anything else may exist, but whatever it is we can never apprehend it.
Patrick McCauley, Otley, West Yorks
I am married to a philosopher and asked him what it is really like. He said it is really as we perceive it, as argued by the philosopher Susan Stebbing, in Philosophy and the Physicists. Neither philosophers nor physicists stop crossing bridges because they are made of atoms and are therefore not really solid. They are solid in the way ordinary people use the word, and crossable for all practical purposes.