As far as I have taken it, we need to establish two things to justify praxeology.
First: How do we come up with the category of action? Where it is from? Where can we find it?
And second: How do we justify seeing other people as actors? What is our justification saying that other people “act” like we do? We can’t see into their private world, so how could we say that they “act”?
The first is the problem of pure praxeology.
And the second is the problem of applied praxeology.
I answer the first in this post, in this post, and in this thread. We observe our own private world and come up with an idea of our own will or volition. This is the province of thymology. In the Austrian school, the idea of our will, of desire, of belief, and so on aren’t scientific: they are just common-sense understandings of those terms. And that explains why people with a “psychological mindset”, that is, people who tend to think of desire, will, belief, and so on in terms of neurons and other brain things, tend to totally misunderstand Austrian economics and its methodology.
And I answer the second in this post. We don’t need to deal with any metaphysical questions like whether people are “really” conscious. We just MODEL them as actors. And this works to predict their movements. The question of whether somebody is “really” conscious is metaphysical. The only thing which Austrian economics needs to establish is that it works to ACT AS IF they are actors. Nothing more.
All of this are very rough.
But where does your response, and your argument that he is being inconsistent come into all of this? Well, you said that he was being inconsistent in criticizing the panphysicalists, positivists, and so on as resting their science on nothing but a fallacy: pragmatism. But I am saying that he wasn’t criticizing them at all; and I go further to say that he used the same justification for his system on purpose!
We should note something very important here. The paragraph which you brought up, where he admits to “moving in a circle” in his justification of causality is essentially just the problem of induction. He was just admitting that his statements about causality were subject to the problem of induction. But, in the other example of his “pragmatic mindset”, which I gave, that is, of him justifying seeing other people as actors simply based on the fact that it “works”, he said that the problem of other consciousnesses is no less intricate than the problem of induction! He understood the connection between his pragmatism with regard to causality and his pragmatism with regard to seeing other people as actors!
In short, I don’t think that he was being inconsistent. He didn’t criticize the panphysicalists and positivists for their pragmatic mindset, but just their application of it. The pragmatic mindset should lead to seeing other people as actors, not as mere movements in space.