The last word is that “une science bien traitée n’est qu’une
langue bien faite.”[1]
Locke’s logic comprises, amid much else, a theory of general terms[2] and of definition, a view of syllogism[3] and a declaration as to the possibility of inference from particular to particular,[4] a distinction between propositions which are certain but trifling, and those which add to our knowledge though uncertain, and a doctrine of mathematical certainty.[5] As to the first, “words become general by being made the signs of general ideas, and ideas become general by separating from them” all “that may determine them to this or that particular existence. By this way of abstraction they are made capable of representing more individuals than one.” This doctrine has found no acceptance. Not from the point of view for which idea means image. Berkeley, though at length the notions of spirits, acts and relations[6] give him pause, prefers the formula which Hume expresses in the phrase that “some ideas are particular in their nature but general in their representation,”[7] and the after-history of “abstraction” is a discussion of the conditions under which one idea “stands for” a group. Not from those for whom general ideas mean schematic concepts, not imageable. The critic from this side has little difficulty in showing that abstraction of the kind alleged still leave the residuum particular this redness, e.g. not redness. It is, however, of the sorts constituted by the representation which his abstraction makes possible that definition is given, either by enumeration of the simple ideas combined in the significance of the sortal name, or “to save the labour of enumerating,” and “for quickness and despatch sake,” by giving the next wider general name and the proximate difference. We define essences of course in a sense, but the essences of which men talk are abstractions, “creatures of the understanding.” Man determines the sorts or nominal essences, nature the similitudes. The fundamentally enumerative character of the process is clearly not cancelled by the recognition that it is possible to abbreviate it by means of technique. So long as the relation of the nominal to the real essence has no other background than Locke’s doctrine of perception, the conclusion that what Kant afterwards calls analytical judgments a priori and synthetic judgments a posteriori exhaust the field follows inevitably, with its corollary, which Locke himself has the courage to draw, that the natural sciences are in strictness impossible. Mathematical knowledge is not involved in the same condemnation, solely because of the “archetypal” character, which, not without indebtedness to Cumberland, Locke attributes to its ideas. The reality of mathematics, equally with that of the ideals of morals drawn from within, does not extend to the “ectypes” of the outer world. The view of reasoning which Locke enunciates coheres with these views. Reasoning from particular to particular, i.e. without the necessity of a general premise, must be possible, and the possibility finds warranty in a consideration of the psychological order of the terms in syllogism. As to syllogism specifically, Locke in a passage,[8] which has an obviously Cartesian ring, lays down four stages or degrees of reasoning, and points out that syllogism serves us in but one of these, and that not the all-important one of finding the intermediate ideas. He is prepared readily to “own that all right reasoning may be reduced to Aristotle’s forms of syllogism,” yet holds that “a man knows first, and then he is able to prove syllogistically.” The distance from Locke to Stuart Mill along this line of thought is obviously but small.
Apart from the adoption by Hume of the association of ideas as the explanatory formula of the school—it had been allowed by Malebranche within the framework of his mysticism and employed by Berkeley in his theory of vision—there are few fresh notes struck in the logic of sensationalism.Hume. The most notable of these are Berkeley’s treatment of “abstract” ideas and Hume’s change of front as to mathematical certainty. What, however, Hume describes as “all the logic I think proper to employ in my reasoning,” viz. his “rules by which to judge cause and effects,”[9] had, perhaps, farther-reaching historical effects than either. In these the single method of Bacon is already split up into separate modes. We have Mill’s inductive methods in the germ, though with an emphasis quite older than Mill’s. Bacon’s form has already in transmission through Hobbes been transmuted into cause as antecedent in the time series. It may, perhaps, be accounted to Hume for righteousness that he declares—whether consistently or not is another matter—that “the same effect never arises but from the same cause,” and that he still follows Bacon in the conception of absentia in proximo. It is “when in any instance we find our expectation disappointed” that the effect of one of “two resembling objects” will be like that of the other that Hume proposes to apply his method of difference.
No scientific discipline, however, with the doubtful exception of descriptive psychology, stands to gain anything from a temper like that of Hume. The whittling away of its formal or organizing rubrics, as e.g., sameness into likeness, is disconcerting to science wherever the significance of the process is realized. It was because the aftermath of Newtonian science was so rich that the scientific faith of naturalism was able to retain a place besides its epistemological creed that a logician of the school could arise whose spirit was in some sort Baconian, but who, unlike Bacon, had entered the modern world, and faced the problems stated for it by Hume and by Newton.
Stuart Mill’s System of Logic marked a fresh stage in the history of empiricism, for the reason that it made the effort to hold an even balance between the two moments in the thought of the school. Agreement in the use of a common watchword had masked as it seems a real divergence of meaningJ. S. Mill. and purpose. The apostles of inductive method had preached recourse to experience, but had meant thereby nature as a constituted order. They had devised canons for the investigation of the concrete problems of this, but had either ignored altogether the need to give an account of the mirroring mind, or, in the alternative had been, with some naïveté, content to assume that their nominalist friends, consistently their allies in the long struggle with traditionalism, had adequately supplied or could adequately supply the need. The exponents of psychological atomism, on the other hand, with the association of ideas for their one principle of agglutination had come to mean by experience the mental phantasmagoria of the individual. They had undermined the foundations of scientific certainty, and so far as the fecundity of contemporary science did not give them pause, were ready, notwithstanding the difference of their starting-point, to acquiesce in the formula as well as the temper of Pyrrhonism. They could concede the triumphant achievement of science only with the proviso that it must be assumed to fall within the framework of their nominalism. Mill aspired after a doctrine of method such as should satisfy the needs of the natural sciences, notably experimental physics and chemistry as understood in the first half of the 19th century and, mutatis mutandis, of the moral sciences naturalistically construed. In uniting with this the Associationism which he inherited, through his father, from Hume, he revealed at once the strength and weakness of the dual conception of naturalism. His rare thoroughness and rarer candour made it at once unnecessary and impossible that the work should be done again.
If judged by what he denies, viz. the formal logic of Hamilton and Mansel, whose Aristotelian and scholastic learning did but accentuate their traditionalism, and whose acquiescence in consistency constituted in Mill’s view a discouragement of research, such as men now incline to attribute at the least equally to Hume’s idealism, Mill is only negatively justified. If judged by his positive contribution to the theory of method he may claim to find a more than negative justification for his teaching in its success. In the field covered by scholastic logic Mill is frankly associationist. He aims at describing what he
- ↑ Condillac, Langue des Calculs, p. 7.
- ↑ Locke, Essay, iii. 3.
- ↑ Id. ib. iv. 17.
- ↑ Loc. cit. § 8.
- ↑ Id. ib. iv. 4, §§ 6 sqq.
- ↑ Berkeley, Of the Principles of Human Knowledge, § 142.
- ↑ Hume, Treatise of Human Nature, i. 1. 7 (from Berkeley, op. cit., introd., §§ 15-16).
- ↑ Essay, iv. 17, § 3.
- ↑ Treatise of Human Nature, i. 3. 15.
