John Locke

“ This, in many cases by a settled habit, – in things whereof we have frequent experience, is performed so constantly and so quick, that we take that for the perception of our sensation which is an idea formed by our judgment ; so that one, viz. that of sensation, serves only to excite the other, and is scarce taken notice of itself ; – as a man who reads or hears with attention and understanding, takes little notice of the characters or sounds, but of the ideas that are excited in him by them. ”

“ Perception the first simple idea of reflection. Perception, as it is the first faculty of the mind exercised about our ideas ; so it is the first and simplest idea we have from reflection, and is by some called thinking in general. Though thinking, in the propriety of the English tongue, signifies that sort of operation in the mind about its ideas, wherein the mind is active ; where it, with some degree of voluntary attention, considers anything. For in bare naked perception, the mind is, for the most part, only passive ”

“ Arises in sensation only when the mind notices the organic impression. This is certain, that whatever alterations are made in the body, if they reach not the mind ; whatever impressions are made on the outward parts, if they are not taken notice of within, there is no perception. Fire may burn our bodies with no other effect than it does a billet, unless the motion be continued to the brain, and there the sense of heat, or idea of pain, be produced in the mind ; wherein consists actual perception. ”

“ Take one in whom decrepit old age has blotted out the memory of his past knowledge, and clearly wiped out the ideas his mind was formerly stored with, and has, by destroying his sight, hearing, and smell quite, and his taste to a great degree, stopped up almost all the passages for new ones to enter ”

“ Which ideas appear first, is not evident, nor important. As there are some ideas which we may reasonably suppose may be introduced into the minds of children in the womb, subservient to the necessities of their life and being there : so, after they are born, those ideas are the earliest imprinted which happen to be the sensible qualities which first occur to them ; amongst which light is not the least considerable, nor of the weakest efficacy. ”

“ Secondly, we shall not be so much surprised that this is done in us with so little notice, if we consider how the facility which we get of doing things, by a custom of doing, makes them often pass in us without our notice. Habits, especially such as are begun very early, come at last to produce actions in us, which often escape our observation. How frequently do we, in a day, cover our eyes with our eyelids, without perceiving that we are at all in the dark ! ”

“ How, by habit, ideas of sensation are unconsciously changed into ideas of judgment. Nor need we wonder that this is done with so little notice, if we consider how quick the actions of the mind are performed. For, as itself is thought to take up no space, to have no extension ”

“ Suppose a man born blind, and now adult, and taught by his touch to distinguish between a cube and a sphere of the same metal, and nighly of the same bigness, so as to tell, when he felt one and the other, which is the cube, which the sphere. ”

“ The effects of sensation in the womb. But though it be reasonable to imagine that children receive some ideas before they come into the world, yet these simple ideas are far from those innate principles which some contend for, and we, above, have rejected. ”

“ And how covetous the mind is to be furnished with all such ideas as have no pain accompanying them, may be a little guessed by what is observable in children new-born ; who always turn their eyes to that part from whence the light comes, lay them how you please. But the ideas that are most familiar at first, being various according to the divers circumstances of children’s first entertainment in the world, the order wherein the several ideas come at first into the mind is very various, and uncertain also ”

“ We are further to consider concerning perception, that the ideas we receive by sensation are often, in grown people, altered by the judgment, without our taking notice of it. When we set before our eyes a round globe of any uniform colour, v.g. ”