A Treatise of Human Nature | Page 5

clear up after the same manner any doubt

in moral philosophy, by placing myself in the same case with that which I consider, it is
evident this reflection and premeditation would so disturb the operation of my natural
principles, as must render it impossible to form any just conclusion from the phenomenon.
We must therefore glean up our experiments in this science from a cautious observation
of human life, and take them as they appear in the common course of the world, by men's
behaviour in company, in affairs, and in their pleasures. Where experiments of this kind
are judiciously collected and compared, we may hope to establish on them a science
which will not be inferior in certainty, and will be much superior in utility to any other of
human comprehension.

BOOK I. OF THE UNDERSTANDING



PART I. OF IDEAS, THEIR ORIGIN,
COMPOSITION, CONNEXION, ABSTRACTION,
ETC.

SECT. I. OF THE ORIGIN OF OUR IDEAS.
All the perceptions of the human mind resolve themselves into two distinct kinds, which I
shall call IMPRESSIONS and IDEAS. The difference betwixt these consists in the
degrees of force and liveliness, with which they strike upon the mind, and make their way
into our thought or consciousness. Those perceptions, which enter with most force and
violence, we may name impressions: and under this name I comprehend all our
sensations, passions and emotions, as they make their first appearance in the soul. By
ideas I mean the faint images of these in thinking and reasoning; such as, for instance, are
all the perceptions excited by the present discourse, excepting only those which arise
from the sight and touch, and excepting the immediate pleasure or uneasiness it may
occasion. I believe it will not be very necessary to employ many words in explaining this
distinction. Every one of himself will readily perceive the difference betwixt feeling and
thinking. The common degrees of these are easily distinguished; though it is not
impossible but in particular instances they may very nearly approach to each other. Thus
in sleep, in a fever, in madness, or in any very violent emotions of soul, our ideas may
approach to our impressions, As on the other hand it sometimes happens, that our
impressions are so faint and low, that we cannot distinguish them from our ideas. But
notwithstanding this near resemblance in a few instances, they are in general so very
different, that no-one can make a scruple to rank them under distinct heads, and assign to
each a peculiar name to mark the difference [Footnote 1.].
[Footnote 1. I here make use of these terms, impression and idea, in a sense different
from what is usual, and I hope this liberty will be allowed me. Perhaps I rather restore the
word, idea, to its original sense, from which Mr LOCKE had perverted it, in making it

stand for all our perceptions. By the terms of impression I would not be understood to
express the manner, in which our lively perceptions are produced in the soul, but merely
the perceptions themselves; for which there is no particular name either in the English or
any other language, that I know of.]
There is another division of our perceptions, which it will be convenient to observe, and
which extends itself both to our impressions and ideas. This division is into SIMPLE and
COMPLEX. Simple perceptions or impressions and ideas are such as admit of no
distinction nor separation. The complex are the contrary to these, and may be
distinguished into parts. Though a particular colour, taste, and smell, are qualities all
united together in this apple, it is easy to perceive they are not the same, but are at least
distinguishable from each other.
Having by these divisions given an order and arrangement to our objects, we may now
apply ourselves to consider with the more accuracy their qualities and relations. The first
circumstance, that strikes my eye, is the great resemblance betwixt our impressions and
ideas in every other particular, except their degree of force and vivacity. The one seem to
be in a manner the reflexion of the other; so that all the perceptions of the mind are
double, and appear both as impressions and ideas. When I shut my eyes and think of my
chamber, the ideas I form are exact representations of the impressions I felt; nor is there
any circumstance of the one, which is not to be found in the other. In running over my
other perceptions, I find still the same resemblance and representation. Ideas and
impressions appear always to correspond to each other. This circumstance seems to me
remarkable, and engages my attention for a moment.
Upon a more accurate survey I find I have been carried away too far by the first