Since everything then is cause and effect, dependent and supporting, mediate and immediate, and all is held together by a natural though imperceptible chain, which binds together things most distant and most different, I hold it equally impossible to know the parts without knowing the whole, and to know the whole without knowing the parts in detail.
And what completes our incapability of knowing things, is the fact that they are simple, and that we are composed of two opposite natures, different in kind, soul and body. For it is impossible that our rational part should be other than spiritual; and if any one maintain that we are simply corporeal, this would far more exclude us from the knowledge of things, there being nothing so inconceivable as to say that matter knows itself. It is impossible to imagine how it should know itself.
So if we are simply material, we can know nothing at all; and if we are composed of mind and matter, we cannot know perfectly things which are simple, whether spiritual or corporeal. Hence it comes that almost all philosophers have confused ideas of things, and speak of material things in spiritual terms, and of spiritual things in material terms.
For they say boldly that bodies have a tendency to fall, that they seek after their centre, that they fly from destruction, that they fear the void, that they have inclinations, sympathies, antipathies, all of which attributes pertain only to mind. And in speaking of minds, they consider them as in a place, and attribute to them movement from one place to another; and these are qualities which belong only to bodies.
Instead of receiving the ideas of these things in their purity, we colour them with our own qualities, and stamp with our composite being all the simple things which we contemplate.