I was reading John Heil’s (fairly brief) discussion of idealism in his philosophy of mind book. It’s an interesting read because he spends most of the time saying that the case for idealism is very strong and it’s extremely difficult to argue against it, but then he throws in a curveball at the end.
The Case for Idealism
He spends a fair bit of the discussion on Berkeley-style arguments about the emptiness of the concept of mind-independent things. Here is a sample, considering a tomato as the supposedly material object of interest:
“Materialist philosophers tell us that these experiences correspond to and are caused by a mind-independent tomato ‘out there’. But, when you examine your conception of tomatoes, you will find only experiences. You will find nothing answer to the expression ‘mind-independent tomato’. The expression ‘mind-independent tomato’, then, is empty of significance. In that regard, it resembles ‘colorless green ideas’. You can utter these words, but they signify nothing. You could, as well, entertain a thought that you might describe as a thought of colorless green ideas. But in so doing, you entertain an empty thought, a thought with no content.
In setting out to imagine a mind-independent tomato, you, in effect, call to mind certain familiar kinds of experience, then subtract from these the idea that they are experiences!”
He also credits idealism with “saving appearances,” in the sense that a universe in which idealism is true is identical to a world in which materialism is true. Put another way, there is no empirical evidence that could cause us to favor materialism over idealism. And idealism offers simpler explanations:
“Idealism certainly covers the bases. It banishes problems associated with causal interaction between minds and the material universe, and it does so in a way that bypasses worries associated with parallelism and occasionalism. Righly understood, idealism is consistent with all the evidence you could possible muster. Moreover, idealism has a kind of elegant simplicity of the sort valued in the sciences. Idealism postulates nothing more than minds and their contents, and explains all the phenomena by appeals to these without needing to resort to messy theories concerning extra-mental material objects and events. Perhaps this is why some scientists, including prominent physicists, have embraced idealism.”
And idealism avoids the bifurcation of reality that infects so many philosophies of mind, including contemporary forms of materialism that have discarded Cartesian dualism but still retain Cartesian internalism (a subject for another post).
We could make an analogy with choosing interpretations of quantum mechanics, where they all make the same predictions, and so we have to judge them by criteria such as simplicity and parsimony. Looking at it that way, what could possibly lead us to choose materialism over idealism?
Interestingly, though, Heil doesn’t wind up an idealist. He doesn’t offer any arguments against it, but essentially says that idealism is too easy. After saying that “there are no obvious chinks in the idealist’s armor,” he concludes that section of the book with this:
“My own suspicion is that idealism represents a kind of failure of nerve: unable to reconcile minds and the material universe, the idealist gives up the game and stuffs the material universe inside the mind.”
I think what’s happening is that he really wants to retain the bifurcation of reality into mind and matter, and he wants a complicated theory that’s going to explain how this bifurcation works. In fact, he hints at this earlier in the section:
“Even so, I predict that you will find idealism hard to swallow. This could be in part because idealism appears to take the easy way out. Idealism explains the appearances by identifying the appearances with reality. Most of us, however, hold out hope that there might be some way to keep the distinction and to reconcile our minds and their contents with a nonmental, mind-independent, material universe.”
In other words, he wants a universe that is divided and a messy theory to stitch it together somehow.
Is this a good argument, that idealism is too clean and simple? Perhaps it would be if idealism failed to account for reality as we know it. Would it be right to criticize an interpretation of quantum mechanics as “too simple” if it makes all the same predictions as every other interpretation, but with fewer assumptions and complications?
Idealism and Pluralism
Having said all that, I am not a committed idealist. Not because I favour materialism over idealism (I don’t), but because I am suspicious of substance monism. I think some sort of pluralism is probably true, where non-substantive things like possibilities, mathematical truths, and perhaps moral truths are just as real as any substantive object. Being a substance is just one way of being.
I think it should be possible to combine this type of ontological pluralism with substance monism. That would be the view that there is one type of substance (which, in the case of idealism, is fundamentally mental), but that substance is only one way of being. Or that idea seems worth exploring, at least.