This piece originally appeared on Quora.com as an answer to the question, “How do metaphysics and epistemology connect?”
This is a really broad question, and it’s hard to get a useful answer to something phrased this way. So please do not take the following too seriously, since I’m painting in very broad strokes. I’m just kind of spitballing here. Just have fun with it.
My gut reaction is to say — despite the fact that my gut reactions are usually wrong — that epistemology plays an essentially limiting role on metaphysics. That is, what kind of metaphysics you have, or whether you have one at all, is heavily dependent on what your epistemology is.
For example, if your epistemology is deeply skeptical, like that of Nietzsche, then you might reject metaphysics on the basis that the “ultimate reality” is unknowable. If, like Nietzsche, you believe that it’s foolhardy to even speak of ultimate reality, then you will say “The bowels of existence speak to man only as man,” and leave it at that. Your epistemology precludes metaphysics.
Kant, on the other hand, would say that there is a realm of things that we cannot hope to know in any great detail (the noumenal) but that a transcendental deduction can help us draw limits to what the mind can do. If that’s the case, then your metaphysics is going to end up being a metaphysics of how your mind constructs the reality you experience, which is exactly what Kant did. If you’re no longer concerned with carving reality at the joints and staking out its essential workings because you believe that to be impossible, then your focus shifts to your own experience and how it comes to be assembled from the whatever-it-is-out-there that gives you your data.
You could also go with a more qualified skepticism, where you say something like this: “There are aspects of experience that do not respond well to idealization. And a you can only fit so much into a conceptual box before it becomes trivial. Over the past few centuries, our philosophical mistakes have come from either not acknowledging this, or acknowledging it in a way that allows the same basic errors to remain.” Something like this is my position. It’s a bit more modest than Nietzsche’s iconoclastic global skepticism (and subsequent relegation of the “true world” to a fable). I suppose I am still indebted to Kant on some level, except that I think the precise little cognitive cage he constructed for us has more cracks than he would suppose, and I think that the success of non-Euclidean geometry — that is, because it is used in physics — is evidence of this. The limits of experience are not only different from what Kant thought they were, but also more malleable.
My epistemology is postmodern in the very basic sense: I don’t think that a comprehensive system in the vein of Leibniz or Spinoza can be built, or even should be. You can’t put it all in one box. I also see some value in the post-structuralists’ critiques of knowledge. However, I think that the zeal to preserve Enlightenment ethics (i.e. equality) has prevented us from coming to terms with the limitations of rationality. The grim truth is that, if you authentically acknowledge the limitations of instrumental rationality, Enlightenment values change radically. But the post-structuralists made an attempt to preserve equality from this transvaluation, which is a glaring weakness of their project. They delayed the inevitable, to their own detriment.
So to summarize: epistemological considerations precede metaphysical ones because the former constrain the latter more than the latter constrain the former. My position — which I do not claim to have presented with any acceptable degree of rigor — is one that allows for modest metaphysical speculation. Thanks for reading!
(By the way, if you want to hear me read Foucault and other philosophers, head on over to my YouTube channel. I livestream on most days.)