– the “in-order-to”, the “for-the-sake-of”, and the “with-which” of an involvement – is such that they resist any sort of mathematical functionalization; nor are they merely something thought, first posited in an ‘act of thinking.’ They are rather relationships in which concernful circumspection as such already dwells. This ‘system of Relations’, as something constitutive for worldhood, is so far from volatilizing the Being of the ready-to-hand within-the-world, that the worldhood of the world provides the basis on which such entities can for the first time be discovered as they are ‘substantially’ ‘in themselves’. And only if entities within-the-world can be encountered at all, is it possible, in the field of such entities, to make accessible what is just present-at-hand and no more. By reason of their Being-just-present-at-hand-and-no-more, these latter entities can have their ‘properties’ defined mathematically in ‘functional concepts.’ Ontologically, such concepts are possible only in relation to entities whose Being has the character of pure substantiality. Functional concepts are never possible except as formalized substantial concepts. BTMR §18
Circumspective concern includes the understanding of a totality of involvements, and this understanding is based upon a prior understanding of the relationships of the “in-order-to”, the “towards-which”, the “towards-this”, and the “for-the-sake-of”. The interconnection of these relationships has been exhibited earlier as “significance”. Their unity makes up what we call the “world”. The question arises of how anything like the world in its unity with Dasein is ontologically possible. In what way must the world be, if Dasein is to be able to exist as Being-in-the-World? BTMR §69
The unity of the horizonal schemata of future, Present, and having been, is grounded in the ecstatical unity of temporality. The horizon of temporality as a whole determines that whereupon [woraufhin] factically existing entities are essentially disclosed. With one’s factical Being-there, a potentiality-for-Being is in each case projected in the horizon of the future, one’s ‘Being-already’ is disclosed in the horizon of having been, and that with which one concerns oneself is discovered in the horizon of the Present. The horizonal unity of the schemata of these ecstases makes possible the primordial way in which the relationships of the “in-orderto” are connected with the “for-the-sake-of”. This implies that on the basis of the horizonal constitution of the ecstatical unity of temporality, there belongs to that entity which is in each case its own “there”, something like’ a world that has been disclosed. BTMR §69