-We can read Descartes’s cogito as saying “that which sees substance (I think) sees existence too (I am)”.
-If one asks evidence for existence or reality, it can only be taken from that realm in which we also find substance, and not from the inferior realm of the sensible as such.
-These two questions are parallel: a.) how do I know that the things I know are real? and b.) how do I know that the things I taste are flavored? What we call knowledge has the real/substance/good as one of its objects, just as taste has flavor as an object. The confusion comes in when we think that we have to give evidence for the real from the sensible order, which is something like asking “how do I touch the scent?” – a question which is either absurd or capable of being aswered only accidentally.
-This is at the heart of the manner: we know what we call the knowledge of somethign with a phsyical or bodily organ: it’s sensation. So…
Whatever is given to a physical organ is given to sense per se.
Reality, goodness, truth, substance, are not given to sense per se but only per accidens.
So the modern problem of objectivity is ultimately a question about the immateriality of the soul.