Unity, uniformity, and development are the three great principles that emerge. We know of no instance where the properties of matter change, though many where a new state of matter develops. The full properties of a molecular compound such as water, for instance, cannot be deduced at present from what we know about the properties of its constituent atoms of hydrogen and oxygen. The properties of the human mind cannot be deduced from our present knowledge of the minds of animals. New combinations and properties thus arise in time. Bergson miscalls such evolution “creative.” We had better, with Lloyd Morgan, call it “emergent.” With mind, we find a gradual evolution from a state in which it is impossible to distinguish mental response from physiological reaction, up to the intensity and complexity of our own emotions and intellect. Since all material developments in evolution can be traced back step by step and shown to be specializations of one or more of the primitive properties of living matter, it is not only an economy of hypothesis, but also, in the absence of any evidence to the contrary, the proper conclusion, that mental properties also are to be traced back to the simplest and most original forms of life. What exact significance is to be attached to the term “mental properties” in such organisms, it is hard to say; we mean, however, that something of the same general nature as mind in ourselves is inherent in all life, something standing in the same relation to living matter in general as do our minds to the particular living matter of our brains. But there can be no reasonable doubt that living matter, in due process of time, originated from non-living; and if that be so, we must push our conclusion farther, and believe that not only living matter, but all matter, is associated with something of the same general description as mind in higher animals. We come, that is, to a monistic conclusion, in that we believe that there is only one fundamental substance, and that this possesses not only material properties, but also properties for which the word _mental_ is the nearest approach. We want a new word to denote this _X_, this world-stuff; _matter_ will not do, for that is a word which the physicists and chemists have moulded to suit themselves, and since they have not yet learned to detect or measure mental phenomena, they restrict the word “material” to mean “non-mental,” and “matter” to mean that which has such “material” properties. You will remember William of Occam’s razor; “Entia non multiplicanda praeter necessitatem”; when we are monists in the sense I have just outlined, we are using that weapon to shave away a very unrestrained growth of hair which has long obscured the features of reality.