Elements of metaphysics

by A. E. Taylor

The fundamental problem for Metaphysics is, of course, whether space and time are ultimate Realities or only appearances; that is, would the whole system of Reality, as directly apprehended by an absolute all-containing experience, wear the forms of extension and succession in time, or is it merely a consequence of the limitations of our own finite experience that things come to us in this guise? It may indeed be urged that the contents of the universe must form an order of some sort for the absolute experience, in virtue of their systematic unity, but even so it is not clear that order as such is necessarily spatial or temporal. Indeed, most of the forms of order with which we are acquainted, both in everyday life and in our mathematical studies, appear to be, properly speaking, both non-spatial and non-temporal. Thus, e.g., it is seemingly by a mere metaphor that we speak of the “successive” integers of the natural number-series, the “successive” powers of an algebraical symbol, the “successive” approximations to the value of a continued fraction, in language borrowed from the temporal flow of events, the true relation involved being in the first two cases the non-temporal one of logical derivation, and in the third the equally non-temporal one of resemblance to an ideal standard. The full solution of the metaphysical problem of space and time would thus involve (1) the discrimination of spatial and temporal order from other allied forms of order, and (2) a decision as to the claim of this special form of order to be ultimately coherent and intelligible.

The problem thus presented for solution is often, and usually with special reference to the Kantian treatment of space and time in the Transcendental Æsthetic, put in the form of the question whether space and time are subjective or objective. This is, however, at best a misleading and unfortunate mode of expression which we shall do well to avoid. The whole distinction between a subjective and an objective factor in experience loses most of its significance with the abolition, now effected by Psychology, of the vicious Kantian distinction between the “given” in perception and the “work of the mind.” When once we have recognised that the “given” itself is constituted by the movement of selective attention, it becomes impossible any longer to distinguish it as an objective factor in knowledge from the subjective structure subsequently raised upon it. Kant’s adherence to this false psychological antithesis so completely distorts his whole treatment of the “forms of intuition,” that it will be absolutely necessary in a brief discussion like our own to deal with the subject in entire independence of the doctrines of the Æsthetic, which unfortunately continue to exercise a disproportionate influence on the current metaphysical presentment of the problem.[^[141]] It should scarcely be necessary to point out that the metaphysical questions have still less to do with the psychological problems, so prominent in recent science, of the precise way in which we come by our perception of extension and succession. For Metaphysics the sole question is one not of the origin but of the logical value of these ideas.

It is of fundamental importance for the whole metaphysical treatment of the subject, to begin by distinguishing clearly between space and time as forms of perception, and space and time as conceptual forms in which we construct our scientific notion of the physical order. One chief source of the confusions which beset the Kantian view is the neglect of Kant and most of his followers to make this distinction with sufficient clearness. We cannot insist too strongly upon the point that the space and the time of which we think in our science as containing the entire physical order, are not space and time as directly known to us in sense-perception, but are concepts elaborated out of the space and time of direct perception by a complicated process of synthesis and analysis, and involving abstraction from some of the most essential features of the space and time of actual experience. The following brief discussion may serve to illustrate the general nature of the relation between the two forms of space and time, and to exhibit the leading differences between them.

§ 2. Perceptual Space and Time. Both space and time, as we are aware of them in immediate perception, are (1) limited. The space we actually behold as we look out before us with a resting eye is always terminated by a horizon which has a more or less well-defined outline; the “specious present,” or portion of duration of which we can be at any time aware at once as an immediately presented content, has been shown by elaborate psychological experimentation to have a fairly well-defined span. Whatever lies outside this “span of attention” belongs either to the no longer presented past or to the not yet presented future, and stands to the sensible present much as the space behind my back to the actually beheld space before my eyes. Of course, in either case the limits of the actually presented space or time are not absolutely defined. To right and left of the line of vision the visible horizon gradually fades off into the indistinctly presented “margin of consciousness”; the “sensible present” shades away gradually at either end into the past and the future. Yet, though thus not absolutely defined, sensible space and time are never boundless.

(2) Perceptual space and time are both internally sensibly continuous or unbroken. Concentrate your attention on any lesser part of the actually seen expanse, and you at once find that it is itself an expanse with all the characteristics of the wider expanse in which it forms a part. Space as actually seen is not an aggregate of minima visibilia or perceptual points in which no lesser parts can be discriminated; so long as space is visually or tactually perceived at all, it is perceived as containing lesser parts which, on attending to them, are found to repeat the characteristics of the larger space. So any part of the “specious present” to which special attention can be directed, turns out itself to be a sensible duration. Perceived space is made of lesser spaces, perceived time of lesser times; the “parts” not being, of course, actually distinguished from each other in the original percept, but being capable of being so distinguished in consequence of varying movements of attention.

(3) On investigating the character of our actual perception of space and time, it appears to contain two aspects, which we may call the quantitative and the qualitative. On the one hand, whenever we perceive space we perceive a certain magnitude of extension, whenever we perceive time we perceive a longer or shorter lapse of duration. Different spaces and different times can be quantitatively compared in respect of the bigness of the extension or the duration comprised in them. On the other hand, the percept of space or time is not one of mere extension or duration. It has a very different qualitative aspect. We perceive along with the magnitude of the extension the form of its outline. This perception of spatial form depends in the last resort upon perception of the direction assumed by the bounding line or lines. Similarly, in dealing with only one dimension of perceived space, we never perceive length (a spatial magnitude) apart from the perception of direction (a spatial quality). The same is true of the perception of time. The lapses of duration we immediately perceive have all their special direction-quality; the “specious present” is essentially a simultaneously presented succession, i.e. a transition from before to after. It must be added that, in perceptual space and time, the directions thus perceived have a unique relation to the perceiving subject, and are thus all qualitatively distinct and irreversible. Direction in space is estimated as right, left, up, down, etc., by reference to axes through the centre of the percipient’s body at right angles to each other, and is thus for any given moment of experience uniquely and unambiguously determined. Direction in time is similarly estimated with reference to the actual content of the “focus of consciousness.” What is actually focal is “now,” what is ceasing to be focal is “past,” what is just coming to be focal is “future” in its direction.[^[142]]

This is perhaps the most fundamental and important peculiarity of the space and time of actual perception. All directions in them are unambiguously determined by reference to the here and now of the immediate experience of an individual subject. As a consequence, every individual subject has his own special perceptual space and time; Geometry and Mechanics depend, to be sure, on the possibility of the establishment of correspondences between these spatial and temporal systems, but it is essential to remember that, properly speaking, the space and time system of each individual’s perception is composed of directions radiating out from his unique here and now, and is therefore individual to himself.[^[143]]

§ 3. The Construction of the Conceptual Space and Time Order of Science. For the purposes of practical life, no less than for the subsequent object of scientific description of the physical order, it is indispensably necessary to establish equations or correspondences between the individual space and time systems of different percipients. Apart from such correspondences, it would be impossible for one subject to translate the spatial and temporal system of any other into terms of his own experience, and thus all practical intercourse for the purpose of communicating directions for action would come to an end. For the communication of such practical directions it is imperative that we should be able mentally to reconstruct the spatial and temporal aspects of our experience in a form independent of reference to the special here and now of this or that individual moment of experience. Thus, like the rest of our scientific constructions, the establishment of a single conceptual space and time system for the whole of the physical order is ultimately a postulate required by our practical needs, and we must therefore be prepared to face the possibility that, like other postulates of the same kind, it involves assumptions which are not logically defensible. The construction is valuable, so far as it does its work of rendering intercommunication between individuals possible; that it should correspond to the ultimate structure of Reality any further than the requirements of practical life demand is superfluous.

The main processes involved in the construction of the conceptual space and time of descriptive science are three,—synthesis, analysis, abstraction. (a) Synthesis. Psychologically speaking, it is ultimately by the active movements of individual percipients that the synthesis of the individual’s various perceptual spaces into one is effected. As attention is successively directed, even while the body as a whole remains stationary, to different parts of the whole expanse before the eye, the visual space which was originally “focal” in presentation becomes “marginal,” and the “marginal” focal by a sensibly gradual transition. When to the movements of head and eyes which accompany such changes in attention there are added movements of locomotion of the whole body, this process is carried further, and we have the gradual disappearance of originally presented spaces from presentation, accompanied by the gradual emergence of spaces previously not presented at all. This leads to the mental construction of a wider space containing all the individual’s different presentation-spaces, the order in which it contains them being determined by the felt direction of the movements required for the transition from one to another.

As we learn, through intercommunication with our fellows, of the existence for their perception of perceptual extension never directly presented to our own senses, the process of synthesis is extended further, so as to comprise in a single spatial system all the presentation-spaces of all the individual percipients in an order once again determined by the direction of the movements of transition from each to the others. Finally, as there is nothing in the principle of such a synthesis to impose limits upon its repetition, we think of the process as capable of indefinite continuance, and thus arrive at the concept of a space stretching out in all directions without definite bounds. This unending repetition of the synthesis of perceived spaces seems to be the foundation of what appears in theory as the Infinity of Space.