CHAPTER VIII.

IDEALISM AND SCIENCE.

A belief in idealism conflicts with the physical sciences in so far as they are concerned with the causes of phenomena.

Idealism consistent with many simple perceptions-Physical science concerns the causes of our perceptions-Examples of scientific prediction― Astronomy-Biology-Evolution-Common sense and "idealism."

consistent

simple

STRANGE as it may at first sight appear to be, it is none Idealism the less true that very many of our ordinary, everyday with many perceptions and experiences fully admit of being expressed perceptions. in idealist phraseology, according to the explanations given of it by its supposed advocate in the foregoing chapter. Stranger still, the idealist representation of these simple experiences of ours is not only easily expressed, but the actual truths of that representation cannot be successfully contested if our perceptions really are, what idealists say they are, perceptions of our own ideas and sensations only. Advocates of idealism mostly confine themselves, as did Bishop Berkeley, to combating objections drawn from a consideration of our ordinary simple perceptions. They speak of perceptions such as our perceptions of an orange. with its various sensible properties, or they discuss our imagination of such things as "a park with trees," or "a library with books," and so on. This mode of procedure was natural, because those who endeavoured to refute idealism made use of objections drawn from a consideration of such simple matters. If physical science was † See above, p. 75.

* See above, p. 73.

Physical

science con

causes of our

merely made up of catalogues of phenomena, simultaneous and successive, of different kinds, the mere number and complexity of those phenomena, however prodigious, would not suffice to make idealist phraseology inapplicable to such science. If an orange may be but a bundle of feelings of different kinds, then the whole contents of a museum, of a geographical region, or of the whole solar system, may also be of similar nature and composition. Physical science, cerns the however, is something very different from a collection of perceptions. catalogues of phenomena. It is a systematic investigation as to what are the causes of different phenomena, and it is also its task to try and explain how such causes act. It appeals, in justification of its declarations about causes, to its own successful predictions, and it is accepted just because its various predictions have again and again been justified by the event. Physical science, therefore, not only has to do with our perceptions, but with the causes of our perceptions. It says not only that we shall have experiences which we call "perceiving new bodies," or "new conditions of bodies," but how and why we shall come to have them.

Examples

of scientific

A prediction like the famed one of Leverrier, affords prediction: a striking example of scientific foresight, based on a belief astronomy. in material bodies acting as causes and acting in a certain manner. Leverrier, by his observations of the planet Uranus-then thought to be the planet most distant from the centre of the solar system-felt sure that its movements must be influenced by the presence of another considerable, but yet unobserved, planet, still more distant from the sun. He also predicted, from a study of those movements, that this as yet unseen planet would be found in a particular place in the heavens at a particular time; and upon the telescope being made use of accordingly, that predicted body was actually for the first time seen, which is now known as the planet Neptune.

Astronomical science in this instance declared not only that we should perceive, under certain conditions, a new body, or, in idealist phrascology, "a new group of feelings," but also how and why we should perceive it. Evidently it really asserted what were the antecedent causes and the

actions of such causes, independently altogether of their being perceived or not perceived. Leverrier's anticipation about Neptune reposed on a conviction of the existence of really existing, independent, extended, material bodies with certain powers, including a really existing force of gravity exerted between Neptune and Uranus, modifying their motions. Let us try to express this in idealist phraseology: The presence of a certain group of feelings I call "Uranus" is accompanied by certain other feelings I call "its movements," and these are succeeded in me by a set of faint feelings I name "an idea of the influence of an external unknown body," together with "a feeling of anticipation" and ideas I call "a particular direction," and "at a particular time." These are again succeeded by other groups of feelings which I call "looking through a telescope at the time and in the direction thought of," after which occurs a final group of feelings which I describe as "seeing the new and predicted planet Neptune."

case.

Over and above the grotesqueness of such modes of expression, which no man of science will feel really and truly portrays his own past mental experience, it is to be remarked that they do not at all represent the facts of the The idealist phraseology puts before us only groups of feelings which co-exist or succeed arbitrarily and without any rational order or any evident reason why they should so co-exist or succeed. The idealist cannot say why the group of feelings he calls "the movements of Uranus should be related to another set of feelings, distinguished as "the influence of an external body," or why the feelings known as “looking through the telescope" should be succeeded by those called "seeing the planet Neptune." If nothing exists but feelings, and some unperceived first cause or agent--whether God or some other existencewhich alone produces them, then everything must depend on the action of that agent, and all secondary causes and interactions, such as those by which one body is supposed to act on another, can be nothing but deceitful, illusory appearances. But since physical science largely consists in a search after secondary causes and the laws of the interaction of bodies one on the other, a system which can take

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Biology.

no account of either, must be simply fatal to physical science. It would seem, then, that though men of science may be idealists, they cannot be so as men of science. While advocating idealism, they must for a time ignore their science; and while pursuing physical science, they must temporarily disregard their idealism, and make use of the hypothesis of the real independent existence of bodies. which alone harmonizes with the teaching of astronomy as exemplified by Leverrier's prediction about the planet Neptune.

The study of living creatures also affords various instructive instances of scientific prediction. A memorable instance of the kind occurred in the career of the great French naturalist, George Cuvier. Amongst the many fossil remains found by him in the vicinity of Paris, was the fossil skeleton of a small beast, embedded for the most part in rock, but with a certain portion of the lower jaw (termed the "angle") exposed. This was bent inwards in a way common to almost all opossums *—animals which also possess two bones imbedded in the flesh of the belly and known to anatomists as "marsupial bones." From his knowledge that these two characters generally went together, Cuvier predicted that a pair of marsupial bones would be found, when that part of the stone which then enclosed the abdominal region of the beast so found by him, should be chiselled away. He invited some friends to be present at the operation, and succeeded in laying bare before them the two bones, the discovery of which he had predicted. But no cause for this co-existence of parts could then or can even now be assigned. A subsequent discovery, therefore, is more germane to the present question. In former times some beasts of vast bulk lived in South America (the megatherium and the mylodon), which more resemble in structure those small existing animals known as "sloths" than they resemble any others. Now, sloths pass their lives hanging, back downwards, from the branches of trees (to which they cling by their four hook-like paws), and the leaves of which they feed on. But the huge extinct animals allied to sloths were evidently too bulky to hang from trees, yet their * See below, chap. xxi.

teeth showed they also fed upon leaves. How did they obtain them? Sir Richard Owen most sagaciously solved this problem. Having duly regarded the rugged outline of the bones of the hind limbs and tail, which indicated the vast masses of muscle which once clothed them, he suggested that these animals had been in the habit of rearing themselves on their hind limbs and tail as on a tripod, and then pulling trees down to feed on their leaves. It was objected to this theory that with such habits these animals would be very apt to get their heads broken by falling trees. Sir Richard thereupon re-examined the head of the mylodon which had been the subject of his investigations and conjectures, and he found that its head had been broken. He also found that the skull of the animal was so constructed as to enable it to endure such fractures with very little inconvenience. Is it possible to relate this circumstance in terms of idealism, without so transforming its significance as to make it mean something altogether different from what was meant by Sir Richard Owen when expounding his views, and what was understood by his hearers when listening to his exposition? Evidently the "falling tree" referred to hypothetically may be thought of as a "plexus of faint feelings," and the fractured skull actually seen may be considered a "plexus of vivid feelings;" but in this way we lose the entire idea of the causation of the fracture by the fall, and the whole point and meaning of Sir Richard's sagacious inference would be thereby missed.

Moreover, according to that inference, the actions of the extinct mylodon and the risks it ran from falling trees, were supposed to be quite independent of any mind perceiving such actions, even if they did not exist at a period anterior to any possible human observation of them whatever. Physical science declares to us not only what we shall perceive under certain conditions, but also, as was just now said, how it comes about that we shall perceive it, and what are the antecedent causes and their actions, independently altogether of anybody perceiving them. It tells us, indeed, Evolution. that there was a time when there were no minds to perceive, and that, nevertheless, the interaction of physical