To begin with the question is: what is a deduction? Kant answers this question in A84/B116: “When teachers of law talk about rights and claims, they distinguish in a legal action the question regarding what is legal (quid juris) from the question concerning fact (quid facti), and they demand proof of both. The first proof, which is to establish the right, or for that matter the legal entitlement, they call the deduction. We employ a multitude of empirical concepts without being challenged by anyone. And we consider ourselves justified, even without having offered a deduction, to assign to these empirical concepts a meaning and imagined signification, because we always have experience available to us to prove their objective reality. But there are also concepts that we usurp, as, e.g. fortune, fate. And although these concepts run loose with our almost universal forbearance, yet they are sometimes confronted by the question of their legality, quid juris. This question then leave
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