The broad definition of the idea in Kant's view reads as follows: "I understand by idea a necessary concept of reason to which no corresponding (kongruierendes) object can be given in sense-experience (in den Sinnen)." ¹ To what extent is the idea a necessary concept of reason? The answer seems to lie in the essence of reason which itself is a system.² Since reason is a system, ideas embody its systematic essence. Yet there is no meeting between the system and its ideas, that is to say, between reason and its ideas on the one hand and objects congruous with them and encountered in sensibility on the other. Since there is no correspondence to ideas on the level of sensibility, we are left with concepts only. Thus ideas are but categories extended to the unconditioned,³ that is to say, categories extended up to the modes of absolute completeness.⁴ "The unconditioned is always contained in the absolute totality of the series," ⁵ Unconditioned or absolute totality amounts to allness (omnitudo) of the reality which is completely determined.⁶