But it is evident at first sight, that the precise length of a line is not different nor distinguishable from the line itself nor the precise degree of any quality from the quality.
These ideas, therefore, admit no more of separation than they do of distinction and difference.

They are consequently conjoined with each other in the conception; and the general idea of a line, notwithstanding all our abstractions and refinements, has in its appearance in the mind a precise degree of quantity and quality; however it may be made to represent others, which have different degrees of both.
Secondly, it is contest, that no object can appear to the senses; or in other words, that no impression can become present to the mind, without being determined in its degrees both of quantity and quality.

The confusion, in which impressions are sometimes involved, proceeds only from their faintness and unsteadiness, not from any capacity in the mind to receive any impression, which in its real existence has no particular degree nor proportion.

That is a contradiction in terms; and even implies the flattest of all contradictions, viz.

that it is possible for the same thing both to be and not to be.
Now since all ideas are derived from impressions, and are nothing but copies and representations of them, whatever is true of the one must be acknowledged concerning the other.