(2.) Objects for concepts, whose objective reality can be proved (whether through pure Reason or through experience, and, in the first case, from its theoretical or practical data, in all cases by means of a corresponding intuition) are _things of fact_ (_res facti_).[147] Of this kind are the mathematical properties of magnitudes (in geometry), because they are susceptible of a _presentation a priori_ for the theoretical use of Reason. Further, things or their characteristics, which can be exhibited in experience (either our own or that of others through the medium of testimony) are likewise things of fact.--And, what is very remarkable, there is one rational Idea (susceptible in itself of no presentation in intuition, and consequently, of no theoretical proof of its possibility) which also comes under things of fact. This is the Idea of _freedom_, whose reality, regarded as that of a particular kind of causality (of which the concept, theoretically considered, would be transcendent), may be exhibited by means of practical laws of pure Reason, and conformably to this, in actual actions, and, consequently, in experience.--This is the only one of all the Ideas of pure Reason, whose object is a thing of fact, and to be reckoned under the _scibilia_. (3.) Objects, which in reference to the use of pure practical Reason that is in conformity with duty must be thought _a priori_ (whether as consequences or as grounds), but which are transcendent for its theoretical use, are mere _things of faith_. Of this kind is the _highest good_ in the world, to be brought about by freedom.[148] The concept of this cannot be established as regards its objective reality in any experience possible for us and thus adequately for the theoretical use of Reason; but its use is commanded by practical pure Reason [in reference to the best possible working out of that purpose],[149] and it consequently must be assumed possible. This commanded effect, _together with the only conditions of its possibility thinkable by us_, viz. the Being of God and the immortality of the soul, are _things of faith_ (_res fidei_), and of all objects are the only ones which can be so called.[150] For though what we learn by _testimony_ from the experience of others must be believed by us, yet it is not therefore a thing of faith; for it was the proper experience of some _one_ witness and so a thing of fact, or is presupposed as such. Again it must be possible by this path (that of historical faith) to arrive at knowledge; and the Objects of history and geography, like everything in general which it is at least possible to know by the constitution of our cognitive faculties, belong not to things of faith but to things of fact. It is only objects of pure Reason which can be things of faith at all, though not as objects of the mere pure speculative Reason: for then they could not be reckoned with certainty among things, _i.e._ Objects of that cognition which is possible for us.