To hate, to love, to think, to feel, to see; all this is nothing but to perceive.
Now since nothing is ever present to the mind but perceptions, and since all ideas are derived from something antecedently present to the mind; it follows, that it is impossible for us so much as to conceive or form an idea of any thing specifically different from ideas and impressions.
Let us fix our attention out of ourselves as much as possible: Let us chase our imagination to the heavens, or to the utmost limits of the universe; we never really advance a step beyond ourselves, nor can conceive any 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.].