Truth is always constrained by its field of application. The purpose if science, if not always of scientists, is to tell us something about the science itself. It may also be used, with extreme caution, to suggest to us something about the world.
Mathematics tells us nothing about the world. It tells us only about mathematics. When we say that something is true in mathematics we mean that it has satisfied a large number of conditions, all of which relate only to the mathematics itself: it is derived from the axioms; it makes transparent use of rigorously manipulated assumptions to go from one step to another; it is general is scope, or defines the limits of its scope if it isn’t general; it subjects itself to rigorous criticism, and openly allows others to analyse and criticise it... then we call it true, but only in the context in which it has validity.
It is logically consistent in its own terms- which it sets out and defines unambiguously- and within its limits of application- likewise described and defined unambiguously.
This what all good science does, but in mathematics it is relatively easy to satisfy the conditions in the previous sentence (or at least it is relatively easy for others to see if we haven’t, which keeps us honest). There is also very little motivation (though it is non-zero) for doing bad mathematics. It many fields it is not so easy to spot the errors, and there can be much greater motivation to unilaterally, and discreetly, relax the conditions.
The soft sciences, the humanities, and philosophy would be taken much more seriously if they applied these conditions to their own research, but sadly, too many of the practitioners in these fields are not even aware that they need to define truth in a way that can have meaning in the field and be consistently used as a test of whether they have in fact discovered anything new, and what it actually tells us, as opposed, for example, to spouting meaningless waffle.
Truth in philosophy can only be absolute, or perhaps it can only exist at all, if its terms are rigidly defined, those definitions are respected at all times, the logic that is used to analyse those terms in terms of one another is both coherent and transparent, and the scope of the results, the limits within which they can be said to be true, are clearly identified. This is perfectly possible, but only a very good philosopher can do it and still produce anything new and interesting.
Spinoza got himself in a terrible mess because, by choosing definitions of his terms which appealed to him at the outset, he had to reduce so much the range of applicability of his results that they tell us nothing useful about God or man as most of us understand him.
Kant did a better job of it, which shows it can be done. But these days it doesn’t make you money, or bring you fame. So most ‘philosophers’, ‘intellectuals’, and ‘thinkers’ that become known are nothing of the kind. People have very little idea of what an intellectual really is, because they don’t appear on television.