Inference also teaches difference

Inference also teaches difference.

Perception thus having for its object only what is marked by difference, inference also is in the same case; for its object is only what is distinguished by connexion with things known through perception and other means of knowledge. And thus, even in the case of disagreement as to the number of the different instruments of knowledge, a thing devoid of difference could not be established by any of them since the instruments of knowledge acknowledged by all have only one and the same object, viz. what is marked by difference. And a person who maintains the existence of a thing devoid of difference on the ground of differences affecting that very thing simply contradicts himself without knowing what he does; he is in fact no better than a man who asserts that his own mother never had any children.