Have I simply accepted a physical/spiritual dualism in a convoluted way by writing in my previous post that I now accept a thesis with the complex name “heterogeneity of truth conditions?” Am I only accepting what Descartes more clearly stated about 400 years ago when he posited two kinds of substances: the physical and the mental?
No! The thesis of heterogeneity of truth conditions is not about what is. It is not an ontological thesis. It is a thesis about our ways of representing what is.
A proof that I am not merely positing Cartesian dualism is that heterogeneity of truth conditions admits that there can be truth conditions for claims about the interaction of mind and body. It is logically consistent to say “I walked across the room because I wanted to get a book off the shelf.” So there can be truth conditions for this claim presupposing that there is mind/body interaction.
But what does the heterogeneity thesis tell us? I admit that its title suggests an ontological thesis. (I am not really satisfied with the title I have given it.) It suggests an ontological thesis of pluralism. It is primarily negative. I suppose that I could just leave it as rejection of homogeneity of truth conditions.
It must be understood in conjunction with the thesis I titled “inscrutability of truth conditions.”
To assert heterogeneity of truth conditions is to concede that there is an unspecifiable variety of ways what exists can form truth conditions. It dismisses all reductionist theses of the form: There is nothing but_______. The blank can be filled in with “physical,” “mental and physical,” etc.,. However, the heterogeneity thesis is not opposed to taking stances such as: There is nothing but _____ for the sake of investigations of _______. Here the second blank can be filled in with a term like “physical” where the physical would have to be defined as perhaps that which can be characterized using only notions of mass, space and time.
It is appropriate to close this short post by noting that heterogeneity of truth conditions is primarily a thesis dismissing all reductionism as misleading unless it is admitted that reductions are only “as if” hypotheses.