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 mentioned.

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
conceived; nor is any thing beyond the power of thought, except what
implies an absolute contradiction.