On the Fourfold Root of the Principle of Sufficient...

Kant's chief passage on the Principle of Sufficient Reason is in a little work entitled "On a discovery, which is to permit us to dispense with all Criticism of Pure Reason."[44] Section I., lit. A. Here he strongly urges the distinction between "the logical (formal) principle of cognition 'every proposition must have its reason,' and the transcendental (material) principle 'every thing must have its cause,'" in his controversy with Eberhard, who had identified them as one and the same.—I intend myself to criticize Kant's proof of the à priori and consequently transcendental character of the law of causality further on in a separate paragraph, after having given the only true proof.

With these precedents to guide them, the several writers on Logic belonging to Kant's school; Hofbauer, Maass, Jakob, Kiesewetter and others, have defined pretty accurately the distinction between reason and cause. Kiesewetter, more especially, gives it thus quite satisfactorily:[45] "Reason of knowledge is not to be confounded with reason of fact (cause). The Principle of Sufficient Reason belongs to Logic, that of Causality to Metaphysics.[46] The former is the fundamental principle of thought; the latter that of experience. Cause refers to real things, logical reason has only to do with representations."

Kant's adversaries urge this distinction still more strongly. G. E. Schultze[47] complains that the Principle of Sufficient Reason is confounded with that of Causality. Salomon Maimon[48] regrets that so much should be said about the sufficient reason without an explanation of what is meant by it, while he blames Kant[49] for deriving the principle of causality from the logical form of hypothetical judgments.

F. H. Jacobi[50] says, that by the confounding of the two conceptions, reason and cause, an illusion is produced, which has given rise to various false speculations; and he points out the distinction between them after his own fashion. Here, however, as is usual with him, we find a good deal more of self-complacent phrase-jugglery than of serious philosophy.

How Herr von Schelling finally distinguishes reason from cause, may be seen in his "Aphorisms introductory to the Philosophy of Nature,"[51] § 184, which open the first book of the first volume of Marcus and Schelling's "Annals of Medecine." Here we are taught that gravity is the reason and light the cause of all things. This I merely quote as a curiosity; for such random talk would not otherwise deserve a place among the opinions of serious and honest inquirers.