It is evident, however, that if logic deals with conceptions which may be considered constitutive of knowledge as such, and if ethics deals with the harmonious realization of human life, which is the highest known form of existence, both sciences must have a great deal of weight in the settling of the general question of metaphysics.
Once more, it would be possible to forget that Mill's ultimate laws or axioms are not in his view intuitions, nor forms constitutive of the rational order, nor postulates of all rational construction, were it not that he has made the endeavour to establish them on associationist lines.
But as ideas,' though of a type quite apart,' they have also a constitutive application to reality.
The point of view is to be modified profoundly by what follows - by the doctrine of the class-concept behind the class, of the form or idea as the constitutive formula of a substance, or, again, by the requirement that an essential attribute must be grounded in the nature or essence of the substance of which it is predicated, and that such attributes alone are admissible predicates from the point of view of the strict ideal of science.
They have not, therefore, like the categories, any constitutive value, and all attempts at metaphysical construction with the notions or categories of science must be resigned as of necessity hopeless.
It carried out Kant's doctrine of the categories as a priori synthetic principles, but removed the limitation by which Kant denied them any constitutive value except in alliance with experience.
The form which a mathematical science treats as relatively self-subsistent is certainly not the constitutive idea.
As contrasted with the first it stood for the necessity of recognizing a universal or ideal element as a constitutive factor in all experience whether cognitive or volitional; as contrasted with the latter for the ultimate unity of subject and object, knowledge and reality, and therefore for the denial of the existence of any thing-in-itself for ever outside the range of experience.