147.] (γ) When this externality (of actuality) is thus developed into a circle of the two categories of possibility and immediate actuality, showing the intermediation of the one by the other, it is what is called Real Possibility. Being such a circle, further, it is the totality, and thus the content, the actual fact or affair in its all-round definiteness. Whilst in like manner, if we look at the distinction between the two characteristics in this unity, it realises the concrete totality of the form, the immediate self-translation of inner into outer, and of outer into inner. This self-movement of the form is Activity, carrying into effect the fact or affair as a _real_ ground which is self-suspended to actuality, and carrying into effect the contingent actuality, the conditions; _i.e._ it is their reflection-in-self, and their self-suspension to an other actuality, the actuality of the actual fact. If all the conditions are at hand, the fact (event) _must_ be actual; and the fact itself is one of the conditions: for being in the first place only inner, it is at first itself only pre-supposed. Developed actuality, as the coincident alternation of inner and outer, the alternation of their opposite motions combined into a single motion, is Necessity. Necessity has been defined, and rightly so, as the union of possibility and actuality. This mode of expression, however, gives a superficial and therefore unintelligible description of the very difficult notion of necessity. It is difficult because it is the notion itself, only that its stages or factors are still as actualities, which are yet at the same time to be viewed as forms only, collapsing and transient. In the two following paragraphs therefore an exposition of the factors which constitute necessity must be given at greater length. * * * * * When anything is said to be necessary, the first question we ask is, Why? Anything necessary accordingly comes before us as something due to a supposition, the result of certain antecedents. If we go no further than mere derivation from antecedents however, we have not gained a complete notion of what necessity means. What is merely derivative, is what it is, not through itself, but through something else; and in this way it too is merely contingent. What is necessary, on the other hand, we would have be what it is through itself; and thus, although derivative, it must still contain the antecedent whence it is derived as a vanishing element in itself. Hence we say of what is necessary, 'It is.' We thus hold it to be simple self-relation, in which all dependence on something else is removed.