Читать книгу An Experiment with Time - J. W. Dunne - Страница 5

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Briefly, then:

Let us suppose that you are entertaining a visitor from some country where the inhabitants are all born blind; and that you are trying to make your guest understand what you mean by 'seeing'. You discover, we will further assume, that the pair of you have, fortunately, this much in common: You are both thoroughly conversant with the meanings of all the technical expressions employed in the physical sciences.

Using this ground of mutual understanding, you endeavour to explain your point. You describe how, in that little camera which we call the 'eye', certain electro-magnetic waves radiating from a distant object are focussed on to the retina, and there produce physical changes over the area affected; how these changes are associated with currents of 'nervous energy' in the criss-cross of nerves leading to the brain-centres, and how molecular or atomic changes at those centres suffice to provide the 'seer' with a registration of the distant object's outline.

All this your visitor could appreciate perfectly.

Now, the point to be noticed is this. Here is a piece of knowledge concerning which the blind man had no previous conception. It is knowledge which he cannot, as you can, acquire for himself by the ordinary process of personal experiment. In substitution, you have offered him a description, framed in the language of physical science. And that substitute has served the purpose of conveying the knowledge in question from yourself to him.

But in 'seeing' there is, of course, a great deal more than mere registration of outline. There is, for example—Colour.

So you continue somewhat on the following lines. That which we call a 'red' flame sets up electro-magnetic waves of a certain length: a 'blue' flame sets up waves exactly similar save only that they differ slightly in this matter of length. The visual organs are so constituted that they sort out waves showing such disparity in length, and this in such a way that these differences are finally registered by corresponding differences in those physical changes which occur at the brain centres.

From the point of view of your blind guest, this description, also, would be entirely satisfactory. He could now understand perfectly how it is that a physical brain is able to register wave-length difference. And, if you were content to leave it at that, he would depart gratefully convinced that the language of physics had again proved equal to the task, and that your description in physical terms had equipped him with a knowledge of, for instance, what other people call 'red' as complete in every respect as that which they themselves possess.

But this supposition of his would be absurd. For concerning the existence of one very remarkable characteristic of red he would still, obviously, know nothing whatsoever. And that characteristic (possibly the most puzzling, and certainly the most obtrusive of them all) is—its redness.

Redness? Yes. Without bothering about whether redness be a thing or a quality or an illusion or anything else, there is no escaping the fact (1) that it is a characteristic of red of which you and all seeing people are very strongly aware, nor the further fact (2) that your visitor, so far, would have not the faintest shadow of an idea that you or others experience anything of the kind, or, indeed, that there could exist anything of the kind to be experienced. If, then, you intend to complete your self-imposed task of bringing his knowledge on the subject of 'seeing' up to the same level as your own, there remains yet another step before you.

Realizing this, you mentally glance down your list of physical expressions, and—a moment's inspection is enough to show you that, for the purpose of conveying to your blind guest a description of redness, there is not a single one of these expressions which is of the slightest use whatsoever.

You might talk to him of particles (lumps—centres of inertia), and describe these as oscillating, spinning, circling, colliding, and rebounding in any kind of complicated dance you cared to imagine. But in all that there would be nothing to introduce the notion of redness. You might speak of waves—big waves, little waves, long waves, and short waves. But the idea of redness would still remain unborn. You might hark back to the older physics, and descant upon forces (attractions and repulsions), magnetic, electrical, and gravitational; or you might plunge forward into the newer physics, and discourse of non-Euclidean space and Gaussian co-ordinates. And you might hold forth on such lines until exhaustion supervened, while the blind man nodded and smiled appreciation; but it is obvious that, at the end of it all, he would have no more suspicion of what it is that (as Ward puts it) 'you immediately experience when you look at a field poppy' than he had at the outset.

Physical description cannot here provide the information which experience could have given.

Now, redness may not be a thing—but it is very certainly a fact. Look around you. It is one of the most staring facts in existence. It challenges you everywhere, demanding, clamouring to be accounted for. And the language of physics is fundamentally unadapted to the task of rendering that account.

It is obvious that dubbing redness an 'illusion' would not help the physicist. For how could physics set about describing or accounting for the entry of the element of redness into that illusion? The universe pictured by physics is a colourless universe, and in that universe all brain-happenings, including 'illusions', are colourless things. It is the intrusion of Colour into that picture, whether as an illusion or under any other title, which requires to be explained.

Once you have thoroughly realized that redness is something beyond a complex of positions, a complex of motions, a complex of stresses, or a mathematical formula, you will have little difficulty in perceiving that Colour is not the only fact of this kind. If your hypothetical visitor were deaf, instead of blind, you could never, by giving him books of physics to read, arouse in him even the beginning of a suspicion regarding the nature of 'Sound', as heard. Now, Sound, as heard, is a fact. (Put down this book and listen.) But in the world described by physics there is no such fact to be found. All that physics can show us is an alteration in the positional arrangement of the brain-particles, or alterations in the tensions acting upon those particles. And in no catalogue of the magnitudes and directions of such changes could there be anything to suggest that there exists anywhere in the universe a phenomenon such as that which you directly experience when a bell tolls. In fact, just as physics cannot deal with the element of redness in 'red', so is it inherently unable to account for the intrusion of that clear bell-note into a universe which it can picture only as an animated diagram of groupings, pushings, and pullings.

But if, in such a diagram, there can be nothing of either Colour or Sound, is it likely to be of any use our hunting therein for phenomena like 'Taste' and 'Smell'? The utmost that we could hope to find would be those movements of the brain-particles which accompany the experiences in question; or, possibly, some day, the transference equations relating to some hitherto unsuspected circuit of energy. Your hypothetical visitor and yourself might each possess the fullest possible knowledge of these brain-disturbances, the most complete acquaintance with such energetic equations as may still remain to be written; but, if you could actually taste and smell, and he could not, it is incontrovertible that your knowledge of each of these phenomena would include something quite unknown to, and, indeed, quite unimaginable by, him.

Now, when we say of any occurrence that it is 'physical', we mean thereby that it is potentially describable in physical terms. (Otherwise the expression would be wholly meaningless.) So it is perfectly correct to state that, in every happening with which our sensory nerves are associated, we find, after we have abstracted therefrom every known or imaginable physical component, certain categorically non-physical residua.

But these remnants are the most obtrusive things in our universe. So obtrusive that, aided and abetted by our trick of imagining them as situated at our outer nerve-endings, or as extending beyond those endings into outer Space, they produce the effect of a vast external world of flaming lights and colours, pungent scents, and clamorous, tumultuous sounds. Collectively, they bulk into a most amazing tempest of sharply-differentiated phenomena. And it is a tempest which remains to be considered after physics has completed its say.

Physics.

Nor is this last a matter for wonderment. For the ideal object of physics is to seek out, isolate, and describe such elements in Nature as may be credited with an existence independent of the existence of any human observer. Physics is, thus, a science which has been expressly designed to study, not the universe, but the things which would supposedly remain in that universe if we were to abstract therefrom every effect of a purely sensory character. From the very outset, then, it renounces all interest in such matters as those colours, sounds, etc., of which we are directly aware,—matters essentially dependent upon the presence of a human observer, and non-existent in his absence,—and it limits itself to a language and a set of conceptions serviceable only for the description of facts pertaining to its own restricted province.

Psychology and Psychical.

But, as scientific investigators of the situation in which we find ourselves, we cannot, of course, neglect to study a mass of phenomena so large and so obtrusive as to constitute, to first appearance, the whole of the world we know. Consequently, a separate science has gradually arisen which endeavours to deal with these and other of the rather bulky leavings of physics. This science is called 'Psychology', and the facts with which it deals are dubbed 'mental', or, more commonly, 'Psychical'.