secret springs and principles, by which the human mind is actuated
in its operations? Astronomers had long contented themselves with
proving, from the phaenomena, the true motions, order, and magnitude
of the heavenly bodies: Till a philosopher, at last, arose, who seems,
from the happiest reasoning, to have also determined the laws and
forces, by which the revolutions of the planets are governed and
directed. The like has been performed with regard to other parts of
nature. And there is no reason to despair of equal success in our
enquiries concerning the mental powers and economy, if prosecuted with
equal capacity and caution. It is probable, that one operation and
principle of the mind depends on another; which, again, may be
resolved into one more general and universal: And how far these
researches may possibly be carried, it will be difficult for us,
before, or even after, a careful trial, exactly to determine. This
is certain, that attempts of this kind are every day made even by
those who philosophize the most negligently: And nothing can be more
requisite than to enter upon the enterprize with thorough care and
attention; that, if it lie within the compass of human
understanding, it may at last be happily achieved; if not, it may,
however, be rejected with some confidence and security. This last
conclusion, surely, is not desirable; nor ought it to be embraced
too rashly. For how much must we diminish from the beauty and value of
this species of philosophy, upon such a supposition? Moralists have
hitherto been accustomed, when they considered the vast multitude
and diversity of those actions that excite our approbation or dislike,
to search for some common principle, on which this variety of
sentiments might depend. And though they have sometimes carried the
matter too far, by their passion for some one general principle; it
must, however, be confessed, that they are excusable in expecting to
find some general principles, into which all the vices and virtues
were justly to be resolved. The like has been the endeavour of
critics, logicians, and even politicians: Nor have their attempts been
wholly unsuccessful; though perhaps longer time, greater accuracy, and
more ardent application may bring these sciences still nearer their
perfection. To throw up at once all pretensions of this kind may
justly be deemed more rash, precipitate, and dogmatical, than even the
boldest and most affirmative philosophy, that has ever attempted to
impose its crude dictates and principles on mankind.

  10. What though these reasonings concerning human nature seem
abstract, and of difficult comprehension? This affords no
presumption of their falsehood. On the contrary, it seems
impossible, that what has hitherto escaped so many wise and profound
philosophers can be very obvious and easy. And whatever pains these
researches may cost us, we may think ourselves sufficiently
rewarded, not only in point of profit but of pleasure, if, by that
means, we can make any addition to our stock of knowledge, in subjects
of such unspeakable importance.

  But as, after all, the abstractedness of these speculations is no
recommendation, but rather a disadvantage to them, and as this
difficulty may perhaps be surmounted by care and art, and the avoiding
of all unnecessary detail, we have, in the following enquiry,
attempted to throw some light upon subjects, from which uncertainty
has hitherto deterred the wise, and obscurity the ignorant. Happy,
if we can unite the boundaries of the different species of philosophy,
by reconciling profound enquiry with clearness, and truth with
novelty! And still more happy, if, reasoning in this easy manner, we
can undermine the foundations of an abstruse philosophy, which seems
to have hitherto served only as a shelter to superstition, and a cover
to absurdity and error!

                 Sect. 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