Thus with the question of the Being of truth and the necessity of presupposing it, just as with the question of the essence of knowledge, an 'ideal subject' has generally been posited. The motive for this, whether explicit or tacit, lies in the requirement that philosophy should have the '*a priori*' as its theme, rather than 'empirical facts' as such. There is some justification for this requirement, though it still needs to be grounded ontologically. Yet is this requirement satisfied by positing an 'ideal subject'? Is not such a subject *a fanciful idealization*? With such a conception have we not missed precisely the *a priori* character of that merely 'factual' subject, Dasein? Is it not an attribute of the *a priori* character of the factical subject (that is, an attribute of Dasein's facticity) that it is in the truth and in untruth equiprimordially?The ideas of a 'pure "I"' and of a 'consciousness in general' are so far from including the *a priori* character of 'actual' subjectivity that the ontological characters of Dasein's facticity and its state of being are either passed over or not seen at all. Rejection of a 'consciousness in general' does not signify that the *a priori* is negated, any more than the positing of an idealized subject guarantees that Dasein has an *a priori* character grounded upon fact.Both the contention that there are 'eternal truths' and the jumbling together of Dasein's phenomenally grounded 'ideality' with an idealized absolute subject, belong to those residues of Christian theology within philosophical problematics which have not as yet been radically extruded.The Being of truth is connected primordially with Dasein. And only because Dasein is as constituted by disclosedness (that is, by understanding), can anything like Being be understood; only so is it possible to understand Being."―from_Being and Time_. Translated by John Macquarrie & Edward Robinson, p. 272
Martin Heidegger
a-priori, heidegger, metaphysics, ontology, philosophy