Holding for true, or the subjective validity of a judgment in relation to conviction (which is, at the same time, objectively valid), has the three following degrees: Opinion, Belief, and Knowledge. Opinion is a consciously insufficient judg ment, subjectively as well as objectively. Belief is subjectively sufficient, but is recognized as being objectively insufficient. Knowledge is both subjectively and objectively sufficient. Subjective sufficiency is termed conviction (for myself); objective sufficiency is termed certainty (for all). I need not dwell longer on the explanation of such simple conceptions.
I must never venture to be of opinion, without knowing something, at least, by which my judgment, in itself merely problematical, is brought into connection with the truth,—which connection, although not perfect, is still something more than an arbitrary fiction. Moreover, the law of such a connection must be certain. For if, in relation to this law, I have nothing more than opinion, my judgment is but a play of the imagination, without the least relation to truth.—In the judgments of pure reason, opinion has no place. For as they do not rest on empirical grounds, and as the sphere of pure reason is that of necessary truth and a priori cognition, the principle of connection in it requires universality and necessity, and consequently perfect certainty,—otherwise we should have no guide to the truth at all. Hence it is absurd to have an opinion in pure mathematics; we must know, or abstain from forming a judgment altogether. The case is the same with the maxims of morality. For we must not hazard an action on the mere opinion that it is allowed, but we must know it to be so.
In the transcendental sphere of reason, on the other hand, the term opinion is too weak, while the word knowledge is too strong. From the merely speculative point of view, therefore, we cannot form a judgment at all. For the subjective grounds of a judgment, such as produce belief, cannot be admitted in speculative enquiries, inasmuch as they cannot stand without empirical support, and are incapable of being communicated to others in equal measure.
But it is only from the practical point of view that a theoretically insufficient judgment can be termed belief. Now the practical reference is either to skill or to morality; to the
