impression. From this constant conjunction of resembling perceptions I
immediately conclude, that there is a great connexion betwixt our
correspondent impressions and ideas, and that the existence of the one
has a considerable influence upon that of the other. Such a constant
conjunction, in such an infinite number of instances, can never arise
from chance; but clearly proves a dependence of the impressions on the
ideas, or of the ideas on the impressions. That I may know on which side
this dependence lies, I consider the order of their first appearance; and
find by constant experience, that the simple impressions always take the
precedence of their correspondent ideas, but never appear in the contrary
order. To give a child an idea of scarlet or orange, of sweet or bitter,
I present the objects, or in other words, convey to him these
impressions; but proceed not so absurdly, as to endeavour to produce the
impressions by exciting the ideas. Our ideas upon their appearance
produce not their correspondent impressions, nor do we perceive any
colour, or feel any sensation merely upon thinking of them. On the other
hand we find, that any impression either of the mind or body is
constantly followed by an idea, which resembles it, and is only different
in the degrees of force and liveliness, The constant conjunction of our
resembling perceptions, is a convincing proof, that the one are the
causes of the other; and this priority of the impressions is an equal
proof, that our impressions are the causes of our ideas, not our ideas
of our, impressions.

To confirm this I consider Another plain and convincing phaenomenon;
which is, that, where-ever by any accident the faculties, which give rise
to any impressions, are obstructed in their operations, as when one is
born blind or deaf; not only the impressions are lost, but also their
correspondent ideas; so that there never appear in the mind the least
traces of either of them. Nor is this only true, where the organs of