Big Al Sun Aug 02, 2009 5:02 pm
Okay, here's my first attempt to work through this question - let me know if I'm missing something...
First, I think it's important not to confuse "objective/subjective facts" with "direct/indirect evidence." An objective fact does not have to be experienced to establish its factualness, while a subjective fact is a fact limited to the subject experiencing it. If I am not experiencing this fact, I can only establish its factualness indirectly, and establishing the reality of this fact depends on the trustworthiness of those who claim to be experiencing this fact (the example in the book of the person with the headache). Many facts, whether objective or subjective, come to me through "indirect evidence" - i.e. I don't experience them myself, but rather rely on indirect evidence of these facts.
"Clear ideas" are ideas that faithfully reflect the objective order from which they derive. Our ideas owe their existence to "objective facts" - things outside and independent of the mind. I know many objective facts through indirect evidence (i.e. I did not experience them myself, but "trust" those who claim to have experienced them). Therefore, I believe it is possible to have a "clear idea" of an "objective fact" that I have never experienced.