Proceed still further. Behind such organic change--assumed to be four-dimensional--there is the determination of some _will-to-live_, which manifests itself to consciousness as thought and as desire. Into these the idea of space does not enter: we think of them as in _time_. But if there are developments of other dimensions of space, thought and emotion may themselves be discovered to have space relations; that is, they may find expression in the forms of _higher_ spaces. Thus is opened up one of those rich vistas in which the subject of the fourth dimension abounds, but into which we can only glance in passing. If there are such higher-dimensional _thought-forms_, our normal consciousness, limited to a world of three dimensions, can apprehend only their three-dimensional aspects, and these not simultaneously, but successively--that is, in _time_. According to this view, any unified series of _actions_--for example, the life of an individual, or of a group--would represent the straining, so to speak, of a thought-form through our _time_, as the bodies subject to these actions would represent its straining through our space. EVOLUTION AS SPACE-CONQUEST Evolution is a struggle for, and a conquest of, space; for evolution, as the word implies, is a _drawing out_ of what is inherent from latency into objective reality, or in other words into spatial--and temporal--extension. This struggle for space, by means of which the birth and growth of organisms is achieved, is the very texture of life, the plot of every drama. Cells subdivide; micro-organisms war on one another; plants contend for soil, light, moisture; flowers cunningly suborn the bee to bring about their nuptials; animals wage deadly warfare in their rivalry to bring more hungry animals into a space-hungry world. Man is not exempt from this law of the jungle. Nations intrigue and fight for land--of which wealth is only the symbol--and a nation's puissance is measured by its power to push forward into the territory of its neighbor. The self-same impulse drives the individual. One measure of the difference between men in the matter of efficiency is the amount of space each can command: one has a house and grounds in some locality where every square inch has an appreciable value; another some fractional part of a lodging house in the slums. When this bloodless, but none the less deadly, contest for space becomes acute, as in the congested quarters of great cities, man's ingenuity is taxed to devise effective ways of augmenting his _space-potency_, and he expands in a vertical direction. This third-dimensional extension, typified in the tunnel and in the skyscraper, is but the latest phase of a conquest of space which began with the line of the pioneer's trail through an untracked wilderness. DIMENSIONAL SEQUENCES