5. Further contradictions appear in Sigwart’s very peculiar and doubtful doctrine concerning the postulates, which he opposes to the axioms. The latter are to be regarded as certain on the ground of their real intellectual necessity; the former, not on the ground of purely intellectual motives, but on psychological motives of another kind, on the ground of practical needs. (Logic, 2nd ed. p. 412 seq.) The law of causality: e.g. is, according to him, not an axiom, but a mere postulate; we regard it as certain, since we find that without affirming it we should not be able to investigate nature. Sigwart, by this mode of accepting the law of causality, that is, affirming, out of mere good-will, that in nature under like conditions, the same results would constantly be forthcoming, manifestly takes it for granted without being conscious of its intellectual necessity. But, if all “taking-as-true” (Fürwahrhalten) is an act of judgment, this is quite incompatible with his views as to the nature of the judgment. Sigwart has here, as far as I can see, but one way of escape, i.e. to confess that he does not believe in what, as a postulate, he accepts as certain (as e.g. the law of causality); then, however, he will be hardly serious in hoping for it.
6. This point becomes still more doubtful on reflection upon what (2) has been previously discussed. The consciousness of a universal necessity of thought does not, according to Sigwart, belong to the postulates, but rather to the axioms. (Cf. 5.) But Sigwart could only with any plausibility exhibit the consciousness of this universal necessity of thinking as operating in the consciousness of one’s personal necessity of thinking by making use of the universal law of causation. But this causal law is itself merely a postulate; it is destitute of self-evidence. It is therefore obvious that the universal thought-necessity in the case of the axioms is also a postulate, and consequently they lose what, according to Sigwart, is their most essential distinction from the postulates. It may perhaps be in accordance with this that Sigwart calls the belief in the trustworthiness of “self-evidence” a postulate. But how the statement so interpreted, can be brought into harmony with the remaining parts of his doctrine I am at a loss to conceive.
7. Sigwart denies (31) the distinction between assertorical and apodictic judgments, since in every judgment the sense of necessity in respect of its function is essential. Consequently this assertion likewise hangs together with his erroneous fundamental view of the judgment; he would appear to identify the feeling which he sometimes calls the feeling of evidence with the apodictic character of a judgment. But it would be quite unjustifiable to overlook the modal peculiarity of certain judgments, as for example, the law of contradiction in distinction from other forms of judgment like that of the consciousness that I am. In the first instance, we have to do with what is “necessarily true or false,” in the second instance only with what is “true or false as a matter of fact,” though both are in the same sense evident and do not differ in respect of their certainty. Only in the case of judgments like the former, not, however, from such as the latter do we draw the notions of impossibility and necessity.
That Sigwart, in opposing the view which regards the apodictic judgment as a special class, also occasionally bears witness against himself is clear from what has been already said (4). The knowledge that I am, he calls, in opposition to the knowledge of an axiom, the knowledge of a simple actual truth (p. 312). Here he speaks more soundly than his general statements would really allow.
Sigwart’s theory of self-evidence is, therefore, essentially false. As in the case of Descartes, so here it cannot be said that Sigwart was not conscious of the phenomenon; indeed, we must rather say in his praise, that with the greatest zeal he has sought to analyze it, but as is the case with many in psychological analysis, it would seem that in the eagerness of analyzing he did not stop at the right point, and has sought to resolve into one another phenomena very distinct in nature.
It is obvious that an error respecting the nature of evidence is fraught with the gravest consequence for the logician. It might well be said that we have here touched upon the deep-seated organic disease in Sigwart’s logic, if this may not rather be said to consist in a misunderstanding of the nature of the judgment in general. Again and again its evil results become manifest, as for example, in Sigwart’s inability to understand the most essential causes of our errors, Cf. Logic, vol. i. 2nd ed. p. 103, note, where, with strange partiality he assigns the chief blame to the defective development of our language.
For the rest, many another celebrated logician in recent times can claim no superiority over Sigwart here. As a further example we need only observe how the doctrine of evidence fares at the hands of the admirable J. S. Mill. Cf. note 69, p. 99.
Owing to the great unclearness as to the nature of evidence, almost universal, it becomes conceivable why, as often happens, we meet with the expression “more or less self-evident.” Even Descartes and Pascal use such expressions, although it is clearly quite unsuitable. Whatever is self-evident is certain, and certainty in the real sense knows no distinctions of degree. Even quite recently we find the opinion expressed in the Vierteljahrsschrift für wissenschaftliche Philosophie (and the writer is manifestly quite serious), that there exist self-evident suppositions which, in spite of their self-evidence, may quite well be false. It is unnecessary to add that I hold this to be opposed to reason. I may here, however, express regret that lectures delivered by me at a time when I still regarded degrees of conviction as intensities of judgment, seem to have given an occasion for such confusions.
[28] (p. 19). Cf. Hume’s Essay, already cited: An Enquiry concerning the Principles of Morals. Other philosophers, who have placed the foundation of ethics in the feelings, as e.g. Beneke and Uberweg (who follows him) have seen further than Hume here. (Cf. the presentation of Beneke’s ethics in his Grundriss der Geschichte der Philosophie, iii.) Herbart comes still nearer to the truth when he speaks of self-evident judgments of taste (these, however, are really not judgments at all, but feelings, and as such are not self-evident, but can only be said to have something analogous to self-evident judgments) and when he further opposes to the merely pleasurable the beautiful, ascribing to the latter as distinct from the former, universal validity and undeniable worth. Unfortunately, there is always something false mixed up with his view, and Herbart loses at once and for ever the right path, so that his ethics in its course diverges much further from the truth than the doctrine of Hume.
Those thinkers who have completely overlooked the distinction between pleasure with the character of rightness and pleasure which is not so qualified, are in danger of falling into opposite errors. The one class view the matter as though all pleasure had the character of rightness, the other class as though no pleasure were so qualified. By the one class the notion of the good as that which rightly pleases, is entirely given up; “worthy of desire” (begehrenswert) in distinction from “desirable” (begehrbar), is an unmeaning expression. For the other class, “worthy of desire” (begehrenswert) remains as a separate notion, so that there is no tautology in their saying nothing is in itself desirable except in so far as it is in itself worthy of desire, is good in itself. Manifestly they must, to be consistent, assert this, and this they have really taught. The extreme hedonists all belong to this class; but, along with them, many others; in the Middle Ages, for example, the teaching is found in Thomas Aquinas, whose greatness receives fresh appreciation from Ihering (cf. Summ. theol. I.a. qu. 80, qu. 82, art. 2 ad. 1, etc.).