and if the second is inadmissible, through default of evidence in its favour, we are left in presence of the first and third. Either special creation, or evolution from infraconsciousness; there is no other alternative.

Accepting as I do the alternative of evolution, I nevertheless see in this evolution the continuous manifestation of a synthetic synthesis, which finds its expression in the primary laws of nature and of mind, and with which I shall deal further in the next chapter. Herein I seem to find the essence of the whole process, that which makes it comprehensible and rational. Regarding man physically and psychically as the crowning product of this evolution, I nevertheless conceive him to be the self-conscious outcome of an activity, selective and synthetic, which is neither energy nor consciousness; which has not been evolved, but through the action of which evolution has been rendered possible; which is neither subject nor object, but underlies and is common to both.

I

CHAPTER XIX.

SELECTIVE SYNTHESIS IN EVOLUTION.

SAID at the end of the last chapter, that in evolution we may see the continuous manifestation of a selective synthesis, which finds its expression in the primary laws of nature and of mind. Allusion has more than once in the course of this work been made to this synthetic tendency in nature; and towards the close of the chapter on Synthesis and Correlation I said that consciousness is essentially a synthetic unity, and that herein we might recognize the subjective aspect of that selective synthesis which we may discern in diverse forms throughout the objective world of nature. I here propose to deal, so far as can be done within reasonable limits, with this selective synthesis. I shall endeavour to present a restatement of the fundamental traits which characterize evolution, and to indicate what I believe to be the essential solidarity of nature in all its modes, inorganic, organic, and conscious. It is, of course, true that the laws of inorganic development are not the same as the laws of organic development; and equally true that the study of mind introduces us to a new aspect of the developmental process. Notwithstanding these obvious differences, the evolution that sweeps through nature is, I believe, one and continuous. My chief concern here is with mental evolution, and it is towards this that I shall throughout be working. But I shall, nevertheless, devote a large share of my space to a consideration of the principles of evolution as they are exemplified first, under the simpler and more rigid conditions of inorganic nature, and then under the complex and plastic conditions of organic development.

If we make a nearly saturated solution of chloride of lead in hot water, and set the solution on one side to cool, we shall see after a while that myriads of minute acicular crystals of chloride of lead make their appearance and sink to the bottom of the vessel in which the solution is contained. Here is a simple case of development or evolution. Let us take note of some of the features it discloses. In the first place the crystals have a definite geometrical form, exhibit differential expansion under the influence of heat, and possess peculiar optical and electrical properties. In a word, the crystals are the result of a selective synthesis, special in its nature, and determinate in its products. Secondly, this selective synthesis can only manifest itself under appropriate environing conditions. If the water be hot, the crystals are not evolved; and if, after they have formed in a cooling solution, the vessel be again heated, the crystals will disappear. Thirdly, if we trace backward the evolution of one of these crystals, we reach a point, that at which the crystal began to form as such, where there is an apparent breach of continuity; by which I mean, not a gap or hiatus in the ascending line of development, but a point of new departure. Such new departures in development are illustrated in Fig. 21, which shows the volume-changes of the substance water under the uniform and continuous application of heat. It will be seen that the line which diagrammatically represents these changes exhibits several points of new departure. Opinions differ as to the exact state in which the chloride of lead exists in the solution, but, whatever that state, there is a critical period when the chloride of lead in solution assumes the form of a solid crystal. Fourthly, it goes without saying that the requisite materials out of which the crystal can be built must be present.

The laws of crystalline synthesis have to a large extent been ascertained, and it is found that all known crystalline

forms fall into one or other of six well-defined groups. There is a remarkable definiteness and, so to speak, narrowness in the limitation of crystalline form. Quartz crystallizes in sixsided prisms capped with hexagonal pyramids, the angles between the faces being of constant value. Though this fundamental form may be modified by the development of additional minor planes, the range of variation is slight. Calcite crystallizes in a greater variety of forms, and there can be little doubt that each one of these is the strictly determinate outcome of crystalline synthesis under the existing conditions of the environment. We must thus regard each several variety of crystalline form as the joint product of what we may term an innate or inherent synthesis and the conditioning of the environment. Were such a crystal endowed with consciousness, we may well suppose that it would claim. freedom to act in accordance with its inherent crystalline nature, except in as far as it was restrained by the inevitable conditions of its environment.

The same general principles are further illustrated in that form of selective synthesis which is shown in the production of chemical compounds. If electric sparks be made to pass between carbon points in an atmosphere of hydrogen, acetylene, a gas containing two atoms of carbon combined with two of hydrogen (C,H2), is formed. If this gas be mixed with hydrogen and caused to pass over spongy platinum, ethene, which has two atoms of carbon and six of hydrogen (CH), is produced. If the acetylene be passed through a red-hot tube, benzene (CH) is formed, together with small quantities of styrene (C,H,), napthalene (CH), and retene (C18H18). If, again, electric sparks be caused to pass through a mixture of acetylene and nitrogen, hydrocyanic acid (HCN) is produced. Similar instances could be multiplied indefinitely. A mixture of carbon monoxide and hydrogen, when it is passed over spongy palladium, gives rise to formaldehyde (CH,O), and six molecules of this in presence of