kind of existence, but those perceptions, which have appeared in that
narrow compass. This is the universe of the imagination, nor have we any
idea but what is there produced.

The farthest we can go towards a conception of external objects, when
supposed SPECIFICALLY different from our perceptions, is to form a
relative idea of them, without pretending to comprehend the related
objects. Generally speaking we do not suppose them specifically
different; but only attribute to them different relations, connections
and durations. But of this more fully hereafter.[Part IV, Sect. 2.]




PART III. OF KNOWLEDGE AND PROBABILITY.



SECT. I. OF KNOWLEDGE.


There are seven [Part I. Sect. 5.] different kinds of philosophical
relation, viz. RESEMBLANCE, IDENTITY, RELATIONS OF TIME AND PLACE,
PROPORTION IN QUANTITY OR NUMBER, DEGREES IN ANY QUALITY, CONTRARIETY and
CAUSATION. These relations may be divided into two classes; into such as
depend entirely on the ideas, which we compare together, and such as may
be changed without any change in the ideas. It is from the idea of a
triangle, that we discover the relation of equality, which its three
angles bear to two right ones; and this relation is invariable, as long
as our idea remains the same. On the contrary, the relations of