text:  Now the great difference between this view of the subject and the views of it that have been taken by _every_ other philosopher consists in this that whereas their explanations invariably implicated the visual sensations _a_ with B from the very first thereby rendering it either impossible for them to be afterwards associated with C or possible only in virtue of some very extravagant hypothesis--our explanation on the contrary proceeding on a simple observation of the facts and never implicating the sensations _a_ with B at all but associating them with C _a primordiis_ merely leaving to be associated with B _a_ a certain general condition that must be complied with in order that the sensations _a_ may be apprehended --in this way we say our explanation contrives to steer clear both of the impossibility and the hypothesis