but they certainly are not identical with the wetness of the roof.

"In the second place, rain is not identical with the wetness of the roof in the sense required here. The rain is detached drops of water falling through the air, the other may be a uniform thin sheet of moisture. They are, from a scientific point of view, different forms of the same matter. But the form is part of the nature of the thing, and, if two things differ in form, they are not identical.

"The other examples show similar defects. And so there are two fatal objections to Hegel's position. He only reaches it, firstly, by taking one Cause of each Effect, although every Effect has many Causes. And, secondly, he only reaches it by assuming that two things are identical if they are formed of the same matter, or if they are of the same value, or have a quantitative equality, ignoring the other aspects in which they differ from one another."1

After some further criticism, McTaggart concludes: "Thus we must reject Hegel's theory of the Identity of Cause and Effect. It is curious that it should have proved one of the most popular of his doctrines. It is often maintained by writers whose works show little study of the detail of other parts of the dialectic."2

This criticism is certainly impregnable so far as it goes. But there is also urgent need of pricking certain other bubbles that float around this doctrine

of the primacy of ground over cause. First, it is often argued that judgments of ground and consequence abstract and mathematical in their character-are convertible, while mere judgments of causality are not so: and this is somehow supposed to give the former a certain prestige over the latter. We can, for instance, convert the proposition, Equilateral triangles are equiangular; but not the proposition, A causes B. But in truth it is the first proposition that is special and subordinate; the equiangularity and the equilaterality are convertible because they are co-existent effects of triangularity or threesidedness; in a four-sided figure there would be no such necessary co-existence of these two attributes or effects. Instead, then, of something wider than causality, we have here only a very narrowly limited and subordinate case of a causal relation.

A second argument is that cause refers only to changes in time and space; but ground-in arithmetic and geometry for example-gives us "eternal truths," immutable facts that will hold good everywhere and forever. I answer that their immutableness is caused by the very nature of pure space or time wherein there is nothing to cause variation. So here again Cause seems to be the primary, supremely significant relation that makes everything else intelligible.

Lotze suggests a third distinction; causes often counteract each other, grounds never do. But he fails to see that the abstract or mathematical sciences deal only with immutable, homogeneous objects—

space and time-and that these by their very nature exclude counteracting or modifying agencies. And so here again we find that ground thus seems to differ from cause, only because it is limited to one special field, while causality operates everywhere. In a word, ground is but one species of cause.

The doctrine of the primacy of ground over cause, then must be dismissed as an idle dream. It was a pardonable error two or three centuries ago, when mathematics was in the first flush of its wonderful development, when the greatest of mathematicians-Descartes and Leibniz-were also the greatest philosophers. But now it seems but the survival of a superstition.

Section 5. Reason and Cause

Here we have another distinction that has given rise to endless doubt and dispute. Among all the strange arguments upon this question, the strangest, perhaps, is Bradley's. The last three chapters of his Logic are mainly devoted to portraying the contrast, or rather, the utter antagonism between cause and reason. But the gist of his entire argument may be exhibited by quoting one of three illustrations which he uses: "Two coins are proven to have similar inscriptions because they each are similar to a third. But the cause is not found in this inter-relation. The cause is the origin from a common die." But surely this is a foolish fallacy. Here are two effects very different from each other; the one effect is two similar inscriptions caused by a common die; the other

effect is our knowledge of this similarity. Of course two effects so different-one psychic, the other physical-could not be the products of the same causal process. But what Bradley fails to see is that although the two processes, knowing and stamping, are different, still both of them are causal processes. There is then no antagonism of reason and cause. Reason is but a special process of causation.

The processes of reason, then, are related to causation as a species to its genus. But there is at this point an error possible which must be avoided. We must not identify the psychic processes of reason with the mechanical processes of Nature. They are different species of the same genus; and their differences are any and extremely important. But it is enough here to designate the one great differentiation which to a certain degree includes all the others. That difference consists in the superior freedom of the psychic processes. For while the course of physical cause is irreversible, the course of thought is not so. Thought is freer than Nature; its movement is not confined to one fixed direction. It can, if it so wills, follow the course of natural events and from the cause go to the effects. Or it can completely reverse that movement and proceed from effects to their causes. Indeed, this reversed movement is thought's supreme prerogative, the source of its greatest victories. Not by deduction from assumed causes to their effects, but by patient scrutiny of and experiment upon observed results-that is the main highway of knowledge.

This superior freedom of thought, this power of reversal, is very significant: as we shall see hereafter it is the key to some of the gravest problems of philosophy. For the present, it is sufficient to see that both ground and reason are species of which cause is the genus.

Section 6. Cause as a Fetish

But the most effective of all objections to the belief in causality is that given in the oft-quoted words of Prof. Mach: "I hope that the science of the future will discard the idea of cause and effect as being formally obscure; and in my feeling that these ideas contain a strong tincture of fetishism I am certainly not alone." And heretofore this objection has indeed been an insuperable one. For plainly, causation is imperceptible; it cannot be seen or handled or heard or tasted or smelled. And to assume offhand, without even pretending to prove that the human mind is mysteriously compelled by some intuition, or innate idea or a-priori necessity of thought to add this idea of cause and effect to what is given, does seem closely akin to the superstition of the savage in regard to his fetish. But if I succeed in establishing my fundamental thesis that all thinking is essentially a relating of cause and effect, then all that will be changed. The belief in causality will no longer be a savage superstition, a mere assumption, a convenient postulate or an unverified hypothesis. On the contrary, it will be the best, the most strictly verified fact within the range of human ex