and then again they also do the opposite of this by dividing other things not according to parts, when the rule is that when one perceives first the community between the members of a group of many things, one should not desist until one sees in it all those differences that are located in classes, and conversely, with the various unlikenesses, when they are seen in multitudes, one should be incapable of pulling a face and stopping before one has penned all the related things within one likeness and actually surrounded them in some real class.