is its 'real' nature, as opposed to its diversity as revealed by analysis. It is an easy step from such particular essences to a universal essence. And the notion of an allgeneral, all-sufficient entity, that shall be all properties to all things, is readily entertained by a mind that is accustomed to the notion of indeterminate and unlimited potentialities. Such are the modes of thought characteristic of a 'metaphysics' that is unfaithful to the method of analysis. Naïve Natural §4. Naïve naturalism regards 'matter,' 'force,' or 'energy' as the universal substance. Such a view is naturalistic, in that it attributes finality and ism. Büchner's universality to these concepts of physical Monism of science; and naïve, in that it puts a substantial rather than an analytical interpre Matter tation on them. During the latter half of the nineteenth century the most influential materialist was Louis Büchner,1 whose Kraft und Stoff has passed through twenty German and eight French editions. This book expressed a reaction against idealistic metaphysics caused by the rapid advance of the natural sciences.2 The author attributes the false philosophy of the past to the abstract separation of matter and force. The former abstracted from the latter-a matter with no internal attraction and repulsion, "a being without properties," is nothing at all ("ein Unding"). The form and movement of matter constitute "its necessary attributes, and sine qua non." On the other hand, force means nothing "without the modifications and movements that we perceive in matter." The absurd notion of a disembodied force is chiefly responsible for the spiritistic and creationist theories which have distinguished loose speculation from true science. "Keine Kraft ohne Stoff, kein Stoff ohne Kraft!" The balance of the chemist proves that matter is "immortal," as the determination of the mechanical equivalent of 11824-1899. The first edition of the Kraft und Stoff appeared in 1855. Cf. op. cit., Conclusion. heat by Mayer and Joule establishes the "immortality" of force.1 In other words, matter manifests itself in force, and force in turn manifests itself in various determinate and measurable changes such as motion and heat. Matter itself is that which thus manifests itself. "This 'something' is what we call matter, the phenomena in question are its activities, and the cause of these activities is the force contained in the substance." What matter is in itself we cannot know. Hence we must not judge matter merely by what is known of it. Indeed since its essence escapes us, there is nothing of which it can be judged incapable. Science is constantly finding it to possess unexpected properties. As a potentiality without assignable limits, it may be as reasonably endowed with "intellectual" force as with "physical" force; and no man can foresee what further powers it may in the future reveal.2 Now it is evident that such a 'monism of matter' necessarily employs the notion of substance - the notion of an essence distinguished from its properties, and not defined by them. Since matter is not identified with specific properties, it is an indefinite potentiality; and were it not so, its universality or metaphysical reality could not be asserted. In short everything can be claimed for matter, just in proportion as matter is not identified with anything in particular. It is the pressure of the speculative dogma, the assumption that there must be some conception having unlimited generality and sufficiency, that leads the party of matter to present their favorite conception in this rôle; and to assume this rôle, matter must be divested of the specific and determinate character which is assigned to it in the limited operations of science. § 5. Now it happens that 'matter' is too well-known in its private capacity to play becomingly the part of Univer 1 Op. cit., from the French translation, by Victor Dave, of the seventeenth edition, pp. 3, 46; cf. Ch. II, III, passim. Op. cit. pp. 43, 45, 46. Spencer's sal Being. Common sense has a comparatively clear image connected with the term. It invariably suggests spacial discreteness and juxtaposition, a tridimensional aggregate of units of volume bounded by hard surfaces. And if this be matter, then evidently matter is not everything. So characteristic an arrangement suggests contrasts as well as analogies; if it provides for some things, like the planetary system or the molecular structure of gases, it leaves out other things, such as color, thought, or the ether. Hence the superiority of concepts like 'force' and 'energy.' For these have not only the specific meaning which they obtain from the formulas of mechanics; they have also the vague meaning which they have when construed in terms of the inner experience of activity or effort. Common sense recoils from the notion of a matter that shall not be hard, discrete, and extended; but it is prepared to hear anything of force or energy. And there is a second motive which tends to the substitution of these conceptions for matter. The indestructibility of matter is proved by the fact that matter changes its form without loss of weight. Empirically, in other words, it is the property of weight that remains constant. But weight is a manifestation of force; and matter may therefore be regarded as one of these manifestations. Or one may argue, as the philosophers Leibniz and Berkeley have argued long since, that matter is known only by its properties, by its "forms and motions"; and if these are varieties of force, why multiply substrata or essences needlessly? Instead of conceiving a matter that manifests itself in forms and motions, why not stop at force, and invest it with finality and universality? So the 'monism of force' replaces 'the monism of matter.' "As shown before," says Spencer, "we can not go on merging derivative truths in those wider truths from which they are derived, without reaching at least a widest truth which can be merged in no other, or derived from no other. And the relation in which it stands to the truths of science in general, shows that this truth transcending demonstration is the Persistence of Force. . . . But when we ask what this energy is, there is no answer save that it is the noumenal cause implied by the phenomenal effect. Hence the force of which we assert persistence is that Absolute Force we are obliged to postulate as the necessary correlate of the force we are conscious of. By the Persistence of Force, we really mean the persistence of some Cause which transcends our knowledge and conception. In asserting it we assert an Unconditioned Reality without beginning or end."1 The use of capitals in this paragraph is an expedient for ridding terms of that precision of meaning which is so fatal to the speculative interest. By 'force' one can only mean the por f of the formulas of mechanics; but by 'Force' one can mean this together with anything else that it may prove convenient to mean. The former is one thing among others; the latter may be equal to anything and everything. We are "obliged to postulate" it, to satisfy the speculative dogma; and we are enabled to satisfy that dogma, only by reducing a determinate concept to a name, and then construing its very emptiness as signifying unlimited potentiality. The monism of force, as has been said, derives a certain plausibility from the experience of activity or effort. It is significant that it is the vagueness of this experience that renders it useful in this connection. Were it a specific experience, like, e.g., that of the color blue, it would not so readily lend itself to unlimited generalization. As a matter of fact, the experience of activity may be construed in one of two ways: it may be taken in its initial or passing character as a fused experience, or it may be analyzed. In the first case, it possesses simplicity just in proportion as it is not an experience of anything; it signifies, not the sim 1 Spencer (1820-1903): First Principles (1862), sixth edition, pp. 175-176. Cf. below pp. 261-264, 279-283. plicity of the thing, but of the knowledge. It is, in short, a case of 'pseudo-simplicity.' In the second case, that is, when analyzed, it turns out to be a composite experience, containing specific elements in a specific configuration. Now activity in the latter sense is far too peculiar and rare to be construed as an all-general and all-sufficient principle. But activity in the former sense is indeterminate; and since the experience is familiar, it gives currency to a similarly indeterminate conception of force, which is amorphous and plastic enough to suit the speculative purpose. It is readily accepted as the principle which underlies and unites both the analyzed and determinate 'force' of physics, and the analyzed and determinate 'activity' of a strictly descriptive psychology. Haeckel's § 6. The monisms of matter and force are restated, brought up to date, and subsumed under a higher "monism of substance," by Ernst Haeckel. Monism of This author's Riddle of the Universe is at present both the most widely read and influential defence of materialism, and also the most perfect illustration of that doctrine's characteristic motive and besetting sins. Substance "Under the name of 'the law of substance,'" Haeckel embraces "two supreme laws of different origin and age the older is the chemical law of the 'conservation of matter,' and the younger is the physical law of the 'conservation of energy. "The sum of matter which fills infinite space,' and "the sum of force, which is at work in infinite space and produces all phenomena," are alike unchangeable. And just as all energies-heat, sound, light, electricity, and the rest, are only particular varieties of one universal energy, "dynamodes of a single primitive force," so the different forms of matter-chemically diverse, ponderable and imponderable, are only particular "condensations" of a "simple primitive substance, which fills the infinity of space in an unbroken continuity." But monism is not yet complete. "Matter (space-filling substance) and |