If a philosopher is not a Berkeley type idealist, s/he acknowledges the source of ideas being external, objective nature (holistically unified, or not), and thus probative investigation requires empirical journeys beyond the boundaries of the explorer's own mind.
— ucarr
Sounds like herein you place your faith in Kant's transcendental idealism, which has the mind's conceptualization limits & biases shaping our view of nature via a priori intuition.
Well, Kant's claims about space & time (the foci of this theory) being necessarily rendered to us by a priori intuition hinges upon discarded Newtonian physics. We now know, in the wake of Einstein, that space & time are out there, impacting our world quite beyond the boundaries of mind. — ucarr
Einstein’s work was fully compatible with Kantian Idealism, while Newton was following Descartes.
If you want to counter by arguing no explorer can get completely beyond one's mental boundaries, then we're venturing into Idealism's skeptical POV on the empirical. Is that where you're coming from? — ucarr
This is what I have in mind. It is indebted to Kant but it is not Kantian idealism. It is Pragmatism and phenomenology:
“ "I follow the trajectory that arises in the later Husserl and continues in Merleau-Ponty, and that calls for a rethinking of the concept of “nature” in a post-physicalist way—one that doesn't conceive of fundamental nature or physical being in a way that builds in the objectivist idea that such being is intrinsically of essentially non-experiential. But, again, this point doesn't entail that nature is intrinsically or essentially experiential (this is the line that pan-psychists and Whiteheadians take). (Maybe it is, but I don't think we're now in position to know that.) All I want to say for now (or think I have grounds for saying now) is that we can see historically how the concept of nature as physical being got constructed in an objectivist way, while at the same time we can begin to conceive of the possibility of a different kind of construction that would be post-physicalist and post-dualist–that is, beyond the divide between the “mental” (understood as not conceptually involving the physical) and the “physical” (understood as not conceptually involving the mental).
“Many philosophers have argued that there seems to be a gap between the objective, naturalistic facts of the world and the subjective facts of conscious experience. The hard problem is the conceptual and metaphysical problem of how to bridge this apparent gap. There are many critical things that can be said about the hard problem (see Thompson&Varela, forthcoming), but what I wish to point out here is that it depends for its very formulation on the premise that the embodied mind as a natural entity exists ‘out there' independently of how we configure or constitute it as an object of knowledge through our reciprocal empathic understanding of one other as experiencing subjects. One way of formulating the hard problem is to ask: if we had a complete, canonical, objective, physicalist account of the natural world, including all the physical facts of the brain and the organism, would it conceptually or logically entail the subjective facts of consciousness? If this account would not entail these facts, then consciousness must be an additional, non-natural property of the world.
One problem with this whole way of setting up the issue, however, is that it presupposes we can make sense of the very notion of a single, canonical, physicalist description of the world, which is highly doubtful, and that in arriving (or at any rate approaching) such a description, we are attaining a viewpoint that does not in any way presuppose our own cognition and lived experience. In other words, the hard problem seems to depend for its very formulation on the philosophical position known as transcendental or metaphysical realism. From the phenomenological perspective explored here, however — but also from the perspective of pragmatism à la Charles Saunders Peirce, William James, and John Dewey, as well as its contemporary inheritors such as Hilary Putnam (1999) — this transcendental or metaphysical realist position is the paradigm of a nonsensical or incoherent metaphysical viewpoint, for (among other problems) it fails to acknowledge its own reflexive dependence on the intersubjectivity and reciprocal empathy of the human life-world.
(Evan Thompson)
Knowledge is taken to consist in a faithful mirroring of a mind-independent reality. It is taken to be of a reality which exists independently of that knowledge, and indeed independently of any thought and experience (Williams 2005, 48). If we want to know true reality, we should aim at describing the way the world is, not just independently of its being believed to be that way, but independently of all the ways in which it happens to present itself to us human beings. An absolute conception would be a dehumanized conception, a conception from which all traces of ourselves had been removed. Nothing would remain that would indicate whose conception it is, how those who form or possess that conception experience the world, and when or where they find themselves in it. It would be as impersonal, impartial, and objective a picture of the world as we could possibly achieve (Stroud 2000, 30). How are we supposed to reach this conception?
Metaphysical realism assumes that everyday experience combines subjective and objective features and that we can reach an objective picture of what the world is really like by stripping away the subjective. It consequently argues that there is a clear distinction to be drawn between the properties things have “in themselves” and the properties which are “projected by us”. Whereas the world of appearance, the world as it is for us in daily life, combines subjective and objective features, science captures the objective world, the world as it is in itself. But to think that science can provide us with an absolute description of reality, that is, a description from a view from nowhere; to think that science is the only road to metaphysical truth, and that science simply mirrors the way in which Nature classifies itself, is – according to Putnam – illusory. It is an illusion to think that the notions of “object” or “reality” or “world” have any sense outside of and independently of our conceptual schemes (Putnam 1992, 120).
Putnam is not denying that there are “external facts”; he even thinks that we can say what they are; but as he writes, “what we cannot say – because it makes no sense – is what the facts are independent of all conceptual choices” (Putnam 1987, 33). We cannot hold all our current beliefs about the world up against the world and somehow measure the degree of correspondence between the two. It is, in other words, nonsensical to suggest that we should try to peel our perceptions and beliefs off the world, as it were, in order to compare them in some direct way with what they are about (Stroud 2000, 27). This is not to say that our conceptual schemes create the world, but as Putnam writes, they don't just mirror it either (Putnam 1978, 1). Ultimately, what we call “reality” is so deeply suffused with mind- and language-dependent structures that it is altogether impossible to make a neat distinction between those parts of our beliefs that reflect the world “in itself” and those parts of our beliefs that simply express “our conceptual contribution.” The very idea that our cognition should be nothing but a re-presentation of something mind-independent consequently has to be abandoned.”
(Dan Zahavi)