The most insidious lie inherent in reductionism, sciencism, subjectivism, naturalism, physicalism, nihilism, whatever name you prefer, is not simply that those who preach it are liars, know that they are liars, nor even that those who listen and ostensibly agree also know they are liars, and are thus themselves liars. Even opposing it in any serious fashion is a collusion with the lie, which is that there is any possible truth in it to begin with. Admitting it as a possibility is already a step towards accepting the arbitrariness of the totalitarian as no different than any other perspective or set of perspectives.
There isn’t a question of ‘being mistaken’, of ‘believing’ it to be true, except in the sense that one wants it to be true and wilfully ignores one’s certain knowledge that it is false, thus the pretense even to being mistaken can be nothing other than lying to oneself. One wants it to be true because it absolves one of responsibility for truth, and concern for the real.
The reason ‘everybody already knows’ it’s a lie, a sham, charlatanry at its worst, is that the simple acts of knowing, speaking, and making that type of a claim demonstrate it to be false in an absolute sense, since they require what it claims to be impossible. That there is an empirical residue in reality, that some things simply are not intelligible, is something nobody who thinks for a moment would deny, but the basic move of all of the ‘positions’ listed above is to eliminate what is intelligible from the field of what can be considered ‘real’ or ‘true’, thus making both truth and reality appear self-contradictory. But the self-contradiction is not in truth or reality, but in the claim that ‘reality’ is not ‘truly’ real, and that truth is not ‘really’ true, which must simultaneously claim it is a ‘true’ statement of reality, a ‘real’ determination of truth.
Making the claim already contradicts itself, and as a result everyone knows it isn’t true, since it contradicts the truth of truth itself and the reality of the real that are presumed and must be presumed in every act of taking into consideration, making determinations, judging the correctness of those determinations and their concrete existence as the actuality of the real, the reality of truth, and the truth of the actual.