In Meditations on First Philosophy, Descartes works to rationally deduce a set of absolutely true principles (much like his famous Discourse on Method), including the existence of matter outside of the mind. Descartes says that his senses pick up involuntary stimuli from matter, and God must have created the ability to detect those stimuli. If these external objects sending out stimuli do not actually exist outside the mind, then God is tricking the mind. Yet God is not a trickster (deceiver). Therefore, external matter exists.
Whether you agree with his argument or not, it poses an interesting question: does matter exist independently of the mind?
An article in the winter 2009 issue of American Scholar discusses this very issue. John Lukacs, from whose article I borrowed the title of this post, says that there cannot be a separation of the knower from the known. This is reminiscent of the idea in quantum physics that by conducting an experiment we alter matter. "In this sense it may even be argued that mind preceded and may precede matter." Matter, he says, did and does exist independently, but without the human mind, matter's existence is meaningless.
Therein lies the second question: assuming matter does exist independently, which comes first, mind or matter?
While not on par with Garth's five cool thought experiments, these two questions fascinate me. Any thoughts?