An Enquiry Concerning Human Understanding HTML version

II. Of The Origin Of Ideas
11. Every one will readily allow, that there is a considerable difference between the
perceptions of the mind, when a man feels the pain of excessive heat, or the pleasure of
moderate warmth, and when he afterwards recalls to his memory this sensation, or
anticipates it by his imagination. These faculties may mimic or copy the perceptions of
the senses; but they never can entirely reach the force and vivacity of the original
sentiment. The utmost we say of them, even when they operate with greatest vigour, is,
that they represent their object in so lively a manner, that we could almost say we feel or
see it: But, except the mind be disordered by disease or madness, they never can arrive at
such a pitch of vivacity, as to render these perceptions altogether undistinguishable. All
the colours of poetry, however splendid, can never paint natural objects in such a manner
as to make the description be taken for a real landskip. The most lively thought is still
inferior to the dullest sensation.
We may observe a like distinction to run through all the other perceptions of the mind. A
man in a fit of anger, is actuated in a very different manner from one who only thinks of
that emotion. If you tell me, that any person is in love, I easily understand your meaning,
and form a just conception of his situation; but never can mistake that conception for the
real disorders and agitations of the passion. When we reflect on our past sentiments and
affections, our thought is a faithful mirror, and copies its objects truly; but the colours
which it employs are faint and dull, in comparison of those in which our original
perceptions were clothed. It requires no nice discernment or metaphysical head to mark
the distinction between them.
12. Here therefore we may divide all the perceptions of the mind into two classes or
species, which are distinguished by their different degrees of force and vivacity. The less
forcible and lively are commonly denominated Thoughts or Ideas. The other species want
a name in our language, and in most others; I suppose, because it was not requisite for
any, but philosophical purposes, to rank them under a general term or appellation. Let us,
therefore, use a little freedom, and call them Impressions; employing that word in a sense
somewhat different from the usual. By the term impression, then, I mean all our more
lively perceptions, when we hear, or see, or feel, or love, or hate, or desire, or will. And
impressions are distinguished from ideas, which are the less lively perceptions, of which
we are conscious, when we reflect on any of those sensations or movements above
13. Nothing, at first view, may seem more unbounded than the thought of man, which not
only escapes all human power and authority, but is not even restrained within the limits
of nature and reality. To form monsters, and join incongruous shapes and appearances,
costs the imagination no more trouble than to conceive the most natural and familiar
objects. And while the body is confined to one planet, along which it creeps with pain
and difficulty; the thought can in an instant transport us into the most distant regions of
the universe; or even beyond the universe, into the unbounded chaos, where nature is
supposed to lie in total confusion. What never was seen, or heard of, may yet be