1/2''Hume taught that we cannot prove the existence of God, of self, or of matter—all of which ideas are the illusions of imagination, having no basis in actual experience. He carried empiricism to the realm of pure skepticism.''~ The Crucible of Modern Though I William Walker Atkinson Empiricism - the conviction that all of our concepts are ultimately drawn from our mind's interpretations of percepts - if taken far enough, inevitably leads to Idealism since matter itself is just another concept and is hence an epiphenomenon of mental activity - which is essentially what the idealists are saying. This is ironic, because most people who identify as idealists profess to believe in innate ideas and deny that the senses can ever be a source of true knowledge. But whereas the rationalist idealist takes his ideas as true, the empiricist idealist is often more inclined to resign himself to skepticism - he's given up all hope of ever knowing anything for certain.If all of our concepts ultimately derive from percepts, then these concepts either reflect some reality outside ourselves (the source of our percepts) or they are just chimeras, figments of our imagination with no existence outside of our mind. If the latter is the case, we can never know anything for certain about the world beyond our percepts and concepts or even if such a hypothetical world exists; so skepticism and agnosticism to the nth degree. If our concepts do correspond to something external to our mind, that means that the world outside of our minds is just another mode of mind because if it were not then there would be nothing for our concepts to correspond to and we'd be back at total skepticism; so idealism.
2/2If all or at least some of our concepts are innate, we are faced with the same dilemma: If our innate concepts do not correspond to anything going on outside of our minds, then all 'knowledge' we might deduce from these concepts is erroneous. If, instead, these innate concepts correspond to something external to our minds, then we must conclude that this external thing that our concepts correspond to is also mental and so we arrive at idealism via a different route.Either way, materialism is refuted if by 'materialism' is meant the notion that matter is the primary substance of which mind is merely an epiphenomenon. Matter is indisputably a concept. If it is a concept, then like all concepts, it is a mode of mental activity and this remains true whether or not we derive our concept of matter from percepts or it is innate; it remains true whether or not the concept of matter exists only in our mind or also exists outside of our mind. In all four of those cases, matter remains a concept and concepts are modes of mind.This is why I see the whole rationalist/empiricist debate as fruitless. It ultimately doesn't matter whether our fundamental ideas (our axioms from which we would deduce all knowledge) are innate or acquired. The only important question is whether or not we should trust these ideas.
