matter, by which alone the same can act, that is, the living plasma. The soul is actual; it is the sum of the physiological functions of the material organs. The human soul is a collective term for a sum of brain functions, and these are like all other life processes conditioned by physical and chemical processes, and hence like all the rest subject to the law of substance.
Let us now see what has become of Haeckel's original monistic theory. According to the original proposition there is one underlying substance of which matter and energy are the attributes. What this substance is, no one knows; perhaps it does not exist at all; perhaps it is force; perhaps prothyl, perhaps ether. But never mind that. We have the two aspects of it in extended space-filling stuff, and the sentient energy. All of a sudden this unitary substance begins to turn itself into a plurality of atoms or pyknatoms; the one becomes the many, monism becomes pluralism. How is this to be explained? It is all very simple to Haeckel. Atoms have souls, feelings and desires, and these properties cause the atoms to contract.
That is, the physical pluralism is explained by assuming a pluralism of forces. But why the unitary substance should desire to differentiate we are not told. But ignoring this difficulty, we note that these atom-souls or soul-atoms, these properties of sensation and will, cause the atoms to contract, and hence cause motion. That is, the attribute of energy, sentient force, mind, thought, or whatever else Haeckel may choose to call it, causes motion, makes matter move, produces a change in the other attribute. Almost in the same breath we are told that there is no form of energy which is not caused by movements of matter.[2] That is, the energy causes the movement, and the motion causes the energy. These statements not only contradict each other, but are out of harmony with the original standpoint of Haeckel, according to which mind and matter are attributes of an underlying substance, dependent upon this and not upon each other.
Haeckel's pure monism, we see, seems to turn into the much-despised dualism. But this is only a passing stage in the philosophical drama. We are hurried on rapidly to the denouement in the chapters on the soul, where the so-called psychical processes become the functions of physiological processes, of physical and chemical changes. We
