“The only thing we can be sure of is…that we can’t be sure of anything.”
In a nutshell, the above statement summarizes Kant and all of Modernism and beyond.
Rationalist Theologians will point to the contradiction inherent in the above formula and use that as justification to dismiss it, and with it, Kant’s entire project.
But to do so I think misses why Kant’s way of thinking has been so successful; that is, that it is honest and therefore more appealing to the human species “nature” as social creatures.
With Kant, we admit we can’t know for sure; with the Rationalist Theologians (much like the Logical Positivists), we make the accusation that something is wrong with you if you don’t accept what we claim.
Going further, we might ask, well if we can’t be sure of anything then what is the best we can do?
In other words, if we can’t answer “what exists?” definitively and can only answer “what exists to us?”, then what is that best way of answering it?
The best answer would likely emerge from us analyzing exactly how the mind itself works.
Active Inference (Friston) gives us a plausible mechanism of a Predictive Brain built on Bayesian Inference.
According to that model, the question of “what exists to us?” is answered simply: “whatever is required to make accurate and consistent predictions of our future”.
And ultimately, I think some of the best evidence for the veracity of Active Inference is going to come by way of demonstration….with Artificial General Intelligence.