capable of producing ideas in us different from what
before they did. The former of these, I think, may be called secondary
qualities IMMEDIATELY PERCEIVABLE: the latter, secondary qualities,
MEDIATELY PERCEIVABLE.

CHAPTER IX.

OF PERCEPTION.

1. 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; and what it
perceives, it cannot avoid perceiving.

2. Reflection alone can give us the idea of what perception is.

What perception is, every one will know better by reflecting on what he
does himself, when he sees, hears, feels, &c., or thinks, than by any
discourse of mine. Whoever reflects on what passes in his own mind
cannot miss it. And if he does not reflect, all the words in the world
cannot make him have any notion of it.

3. 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.

4. Impulse on the organ insufficient.

How often may a man observe in himself, that whilst his mind is intently
employed in the contemplation of some objects, and curiously surveying
some ideas that are there, it takes no notice of impressions of sounding
bodies made upon the organ of hearing, with the same alteration that
uses to be for the producing the idea of sound? A sufficient impulse
there may be on the organ; but it not reaching the observation of the
mind, there follows no perception: and though the motion that uses to
produce the idea of sound be made in the ear, yet no sound is heard.
Want of sensation, in this case, is not through any defect in the organ,
or that the man's ears are less affected tha