Why this Critique is not entitled a Critique of Pure Practical Reason but simply a Critique of Practical Reason generally, although its parallelism with the speculative seems to require the first, is sufficiently explained in this treatise. It has merely to show that there is pure practical reason, and for this purpose it criticizes reason’s entire practical faculty. If it succeeds in this it has no need to criticize the pure faculty itself in order to see whether reason is merely making a claim in which it presumptuously oversteps itself (as does happen with speculative reason). For, if as pure reason it is really practical, it proves its reality and that of its concepts by what it does and all subtle reasoning against the possibility of its being practical is futile.

With this faculty transcendental freedom is also established, taken indeed in that absolute sense in which speculative reason needed it, in its use of the concept of causality, in order to rescue itself from the antinomy into which it unavoidably falls when it wants to think the unconditioned in the series of causal connection; this concept, however, it could put forward only problematically, as not impossible to think, without assuring it objective reality, and only lest the supposed impossibility of what it must at least allow to be thinkable call its being into question and plunge it into an abyss of skepticism.