Cf. Fichte's words (Werke, ii. 255), Aus dem Gewissen allein stammt die Wahrheit, &c.
P. [122], § 62. The Letters on the doctrine of Spinoza, published in 1785, were re-issued in 1789 with eight supplements.
'A science,' says Jacobi in his latest utterance (Werke, iv. pref. xxx.) 'is only a systematic register of cognitions mutually referring to one another—the first and last point in the series is wanting.'
P. [123], § 62. Lalande's dictum is referred to by Fries (Populäre Vorlesungen über Sternkunde, 1813) quoted by Jacobi in his Werke, ii. 55. What Lalande has actually written in the preface to his work on astronomy is that the science as he understands it has no relation to natural theology—in other words, that he is not writing a Bridgewater treatise.
P. [123], § 63. Jacobi, Werke, ii. 222. 'For my part, I regard the principle of reason as all one with the principle of life.' And ii. 343: 'Evidently reason is the true and proper life of our nature.' It is in virtue of our inner tendency and instinct towards the eternal (Richtung und Trieb auf das Ewige),—of our sense for the supersensible—that we, human beings, really subsist (iv. 6. 152). And this Organ der Vernehmung des Uebersinnlichen is Reason (iii. 203, &c.).
The language of Jacobi fluctuates, not merely in words, but in the intensity of his intuitionalism. Thus, e.g. iii. 32: 'The reason man has is no faculty giving the science of the true, but only a presage' (Ahndung des Wahren). 'The belief in a God,' he says, at one time (iii. 206) 'is as natural to man as his upright position': but that belief is, he says elsewhere, only 'an inborn devotion (Andacht) before an unknown God.' Thus, if we have an immediate awareness (Wissen) of God, this is not knowledge or science (Wissenschaft). Such intuition of reason is described (ii. 9) as 'the faculty of presupposing the intrinsically (an sich) true, good, and beautiful, with full confidence in the objective validity of the presupposition.' But that object we are let see only in feeling (ii. 61). 'Our philosophy,' he says (iii. 6) 'starts from feeling—of course an objective and pure feeling.'
P. [124], § 63. Jacobi (Werke, iv. a, p. 211): 'Through faith (Glaube) we know that we have a body.' Such immediate knowledge of our own activity—'the feeling of I am, I act' (iii. 411)—the sense of 'absolute self-activity' or freedom (of which the 'possibility cannot be cognised,' because logically a contradiction) is what Jacobi calls Anschauung (Intuition). He distinguishes a sensuous, and a rational intuition (iii. 59).
P. [125], § 63. Jacobi expressly disclaims identification of his Glaube with the faith of Christian doctrine (Werke, iv. a, p. 210). In defence he quotes from Hume, Inquiry V, and from Reid, passages to illustrate his usage of the term 'belief—by the distinction between which and faith certain ambiguities are no doubt avoided.