Part 44

This Latin dissertation on Motion, or change of place in the component atoms of the material world, was written in 1720, when Berkeley was returning to Ireland, after he had spent some years in Italy, on leave of absence from Trinity College. A prize for an essay on the “Cause of Motion,” had, it seems, been offered in that year by the Paris Academy of Sciences. The subject suggested an advance on the line of thought pursued in Berkeley’s _Principles_ and _Dialogues_. The mind-dependent reality of the material world, prominent in those works, was in them insisted on, not as a speculative paradox, but mainly in order to shew the spiritual character of the Power that is continually at work throughout the universe. This essay on what was thus a congenial subject was finished at Lyons, and published early in 1721, soon after Berkeley arrived in London. It was reprinted in his _Miscellany_ in 1752. I have not found evidence that it was ever submitted to the French Academy. At any rate the prize was awarded to Crousaz, the well-known logician and professor of philosophy at Lausanne.

The _De Motu_ is interesting biographically as well as philosophically, as a revelation of Berkeley’s way of thinking about the causal relations of Matter and Spirit seven years after the publication of the _Dialogues_. In 1713 his experience of life was confined to Ireland. Now, after months in London, in the society of Swift, and Pope, and Addison, he had observed nature and men in France and Italy. His eager temperament and extraordinary social charm opened the way in those years of travel to frequent intercourse with famous men. This, for the time, superseded controversy with materialism and scepticism, and diverted his enthusiasm to nature and high art. One likes to see how he handles the old questions as they now arise in the philosophical treatment of motion in space, which was regarded by many as the key to all other phenomena presented in the material world.

For one thing, the unreality of the data of sense after total abstraction of living mind, the chief Principle in the earlier works, lies more in the background in the _De Motu_. Yet it is tacitly assumed, as the basis of an argument for the powerlessness of all sensible things, and for refunding all active power in the universe into conscious agency. _Mens agitat molem_ might be taken as a motto for the _De Motu_. Then there is more frequent reference to scientific and philosophical authorities than in his more juvenile treatises. Plato and Aristotle are oftener in view. Italy seems to have introduced him to the physical science of Borelli and Torricelli. Leibniz, who died in 1716, when Berkeley was in Italy, is named by him for the first time in the _De Motu_. Perhaps he had learned something when he was abroad about the most illustrious philosopher of the time. And it is interesting by the way to find in one of those years what is, I think, the only allusion to Berkeley by Leibniz. It is contained in one of the German philosopher’s letters to Des Bosses, in 1715. “Qui in Hybernia corporum realitatem impugnat,” Leibniz writes, “videtur nec rationes afferre idoneas, nee mentem suam satis explicare. Suspicor esse ex eo hominum genere qui per Paradoxa cognosci volunt.” This sentence is interesting on account of the writer, although it suggests vague, and perhaps second-hand knowledge of the Irishman and his principles. The name of Hobbes does not appear in the _De Motu_. Yet one might have expected it, in consideration of the supreme place which motion takes in his system, which rests upon the principle that all changes in the universe may be resolved into change of place.

In the _De Motu_ the favourite language of ideal realism is abandoned for the most part. “Bodies,” not “ideas of sense,” are contrasted with mind or spirit, although body still means significant appearance presented to the senses. Indeed the term _idea_ occurs less often in this and the subsequent writings of Berkeley.

I will now give some account of salient features in the _De Motu_.

‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐

Like the _Principles_ the tract opens with a protest against the empty abstractions, and consequent frivolous discussions, which even mechanical science had countenanced although dealing with matters so obvious to sense as the phenomena of motion. _Force_, _effort_, _solicitation of gravity_, _nisus_, are examples of abstract terms connected with motion, to which nothing in what is presented to the senses is found to correspond. Yet corporeal power is spoken of as if it were something perceptible by sense, and so found _within_ the bodies we see and touch (sect. 1-3).

But it turns out differently when philosophers and naturalists try to imagine the _physical force_ that is supposed to inhabit bodies, and to explain their motions. The conception of motion has been the parent of innumerable paradoxes and seeming contradictions among ancient Greek thinkers; for it presents, in a striking form, the metaphysical difficulties in the way of a reconciliation of the One and the Many—difficulties which Berkeley had already attributed to perverse abstractions, with which philosophers amused themselves and blocked up the way to concrete knowledge; first wantonly raising a dust, and then complaining that they could not see. Nor has modern mechanical science in this respect fared better than the old philosophies. Even its leaders, Torricelli, for instance, and Leibniz, offer us scholastic shadows—empty metaphysical abstractions—when they speak about an active power that is supposed to be lodged within the things of sense. Torricelli tells us that the forces within the things around us, and within our own bodies, are “subtle quintessences, enclosed in a corporeal substance as in the enchanted vase of Circe”; and Leibniz speaks of their active powers as their “substantial form,” whatever that can be conceived to mean. Others call the power to which change of place is due, the hylarchic principle, an appetite in bodies, a spontaneity inherent in them; or they assume that, besides their extension, solidity, and other qualities which appear in sense, there is also something named force, latent in them if not patent—in all which we have a flood of words, empty of concrete thought. At best the language is metaphorical (sect. 2-9).

For showing the active cause at work in the production of motion in bodies, it is of no avail to name, as if it were a datum of sense, what is not presentable to our senses. Let us, instead, turn to the only other sort of data in realised experience. For we find only two sorts of realities in experience, the one sort revealed by our senses, the other by inward consciousness. We can affirm nothing about the contents of _bodies_ except what our senses present, namely, concrete things, extended, figured, solid, having also innumerable other qualities, which seem all to depend upon change of place in the things, or in their constituent particles. The contents of _mind_ or _spirit_, on the other hand, are disclosed to inner consciousness, which reveals a sentient Ego that is actively percipient and exertive. And it must be in the second of these two concrete revelations of reality, that active causation, on which motion and all other change depends, is to be found—not in empty abstractions, covered by words like _power_, _cause_, _force_, or _nisus_, which correspond to nothing perceived by the senses (sect. 21).

So that which we call body presents _within itself_ nothing in which change of place or state can originate causally. Extension, figure, solidity, and all the other perceptible constituents of bodies are appearances only—passive phenomena, which succeed one another in an orderly cosmical procession, on which doubtless our pains and pleasures largely depend. But there is no sensibly perceptible power found among those sensuous appearances. They can only be _caused causes_, adapted, as we presuppose, to signify to us what we may expect to follow that appearance. The reason of their significance, i.e. of the constancy of their sequences and coexistences, must be sought for _outside of themselves_. Experimental research may discover new terms among the correlated cosmical sequences or coexistences, but the newly discovered terms must still be only passive phenomena previously unperceived. Body means only what is presentable to the senses. Those who attribute to it something not perceptible by sense, which they call the force or power in which its motions originate, say in other words that the origin of motion is unknowable by sense (sect. 22-24).

Turn now from things of sense, the data of perception, to Mind or Spirit, as revealed in inner consciousness. Here we have a deeper and more real revelation of what underlies, or is presupposed in, the passive cosmical procession that is presented to the senses. Our inward consciousness plainly shews the thinking being actually _exercising_ power to move its animated body. We find that we can, by a causal exertion of which we are distinctly conscious, either excite or arrest movements in bodies. In voluntary exertion we have thus a concrete example of force or power, _producing_ and not merely _followed by_ motion. In the case of human volition this is no doubt conditioned power; nevertheless it exemplifies Power on a greater scale than human, even Divine power, universally and continuously operative, in all natural motions, and in the cosmical laws according to which they proceed (sect. 25-30).

Thus those who pretend to find force or active causation _within_ bodies, pretend to find what their sensuous experience does not support, and they have to sustain their pretence by unintelligible language. On the other hand, those who explain motion by referring it to conscious exertion of personal agents, say what is supported by their own consciousness, and confirmed by high authorities, including Anaxagoras, Plato, Aristotle, Descartes, and Newton, demonstrating that in Spirit only do we find power to change its own state, as well as the states and mutual relations of bodies. Motion in nature is God continuously acting (sect. 31-34). But physical science is conveniently confined to the order of the passive procession of sensuous appearances, including experiments in quest of the rules naturally exemplified in the motions of bodies: reasoning on mathematical and mechanical principles, it leaves the contemplation of active causation to a more exalted science (sect. 35-42).

‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐

In all this it can hardly be said that Berkeley has in this adequately sounded the depths of Causation. He proclaims inability to find through his senses more than sequence of significant sensuous appearances, which are each and all empty of active power; while he apparently insists that he _has_ found active power in the mere _feeling __ of exertion_; which after all, as such, is only one sort of antecedent sign of the motion that is found to follow it. This is still only sequence of phenomena; not active power. But is not causation a relation that cannot be truly presented empirically, either in outer or inner consciousness? And is not the Divine order that is presupposed by us in all change, a presupposition that is inevitable in trustworthy intercourse with a changing universe; unless we are to confess _atheistically_, that our whole sensuous experience may in the end put us to utter confusion? The passive, uneasy feeling of strain, more or less involved in the effort to move our bodies and their surroundings, is no doubt apt to be confused with active causation; for as David Hume remarks, “the animal _nisus_ which we experience, though it can afford no accurate precise idea of power, enters very much into the vulgar, inaccurate idea which is formed of it.” So when Berkeley supposes that he has found a concrete example of originating power in the _nisus_ of which we are conscious when we move our bodies, he is surely too easily satisfied. The _nisus_ followed by motion is, _per se_, only a natural sequence, a caused cause, which calls for an originating cause that is _absolutely_ responsible for the movement. Is not the index to this absolutely responsible agency an ethical one, which points to a free moral agent as alone necessarily connected with, or responsible for, the changes which _he can_ control? Persons are causally responsible for their own actions; and are accordingly pronounced good or evil on account of acts of will that are not mere caused causes—passively dependent terms in the endless succession of cosmical change. They must originate in self, be absolutely self-referable, in a word supernatural issues of the personality. Moral reason implies that they are not determined _ab extra_, and so points to moral agents as our only concrete examples of independent power; but this only so far as those issues go for which they are morally responsible. Is not faith in the Universal Power necessarily faith-venture in the absolutely perfect and trustworthy moral agency of God?

‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐

While the principle of Causation, in its application to change of place on the part of bodies and their constituent atoms, is the leading thought in the _De Motu_, this essay also investigates articulately the nature of the phenomenon which we call _motion_ (sect. 43-66). It assumes that motion is only an effect, seeing that no one who reflects can doubt that what is presented to our senses in the case of motion is altogether passive: there is nothing in the successive appearance of the same body in different places that involves action on the part of either of the moving or the moved body, or that can be more than inert effect (sect. 49). And all concrete motion, it is assumed, must be something that can be perceived by our senses. Accordingly it must be a perceptible _relation between bodies_, as far as it is bodily: it could make no appearance at all if space contained only one solitary body: a plurality of bodies is indispensable to its appearance. Absolute motion of a solitary body, in otherwise absolutely empty space, is an unmeaning abstraction, a collocation of empty words. This leads into an inquiry about relative space as well as relative place, and the intelligibility of absolute space, place, and motion (sect. 52-64).

Local motion is unintelligible unless we understand the meaning of _space_. Now some philosophers distinguish between absolute space, which with them is ultimately the only real space, and that which is conditioned by the senses, or relative. The former is said to be boundless, pervading and embracing the material world, but not itself presentable to our senses; the other is the space marked out or differentiated by bodies contained in it, and it is in this way exposed to our senses (sect. 52). What must remain after the annihilation of all bodies in the universe is relativeless, undifferentiated, absolute space, of which all attributes are denied, even its so-called extension being neither divisible nor measurable; necessarily imperceptible by sense, unimaginable, and unintelligible, in every way unrealisable in experience; so that the words employed about it denote _nothing_ (sect. 53).

It follows that we must not speak of the real space which a body occupies as part of a space that is necessarily abstracted from all sentient experience; nor of real motion as change within absolute space, without any relation between bodies, either perceived or conceived. All change of place in one body must be relative to other bodies, among which the moving body is supposed to change its place—our own bodies which we animate being of course recognised among the number. Motion, it is argued, is unintelligible, as well as imperceptible and unimaginable, without some relation between the moving body and at least one other body: the truth of this is tested when we try to suppose the annihilation of all other bodies, our own included, and retain only a solitary globe: absolute motion is found unthinkable. So that, on the whole, to see what motion means we must rise above the mathematical postulates that are found convenient in mechanical science; we must beware of empty abstractions; we must treat motion as something that is real only so far as it is presented to our senses, and remain modestly satisfied with the perceived relations under which it then appears (sect. 65-66).

‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐

Finally, is motion, thus explained, something that can be spoken of as an entity communicable from one body to another body? May we think of it as a datum of sense existing in the striking body, and then passing from it into the struck body, the one losing exactly as much as the other receives? (sect. 67). Deeper thought finds in those questions only a revival of the previously exploded postulate of “force” as _something sensible_, yet distinct from all the significant appearances sense presents. The language used may perhaps be permitted in mathematical hypotheses, or postulates of mechanical science, in which we do not intend to go to the root of things. But the obvious fact is, that the moving body shews less perceptible motion, and the moved body more. To dispute whether the perceptible motion acquired is numerically the same with that lost leads into frivolous verbal controversy about Identity and Difference, the One and the Many, which it was Berkeley’s aim to expel from science, and so to simplify its procedure and result. Whether we say that motion passes from the striking body into the struck, or that it is generated anew within the struck body and annihilated in the striking, we make virtually the same statement. In each way of expression the facts remain, that the one body presents perceptible increase of its motion and the other diminution. Mind or Spirit is the active cause of all that we then see. Yet in mechanical science—which explains things only physically, by shewing the significant connexion of events with their mechanical rules—terms which seem to imply the conveyance of motion out of one body into another may be pardoned, in consideration of the limits within which physical science is confined, and its narrower point of view. In physics we confine ourselves to the sensuous signs which arise in experience, and their natural interpretation, in all which mathematical hypotheses are found convenient; so that gravitation, for example, and other natural rules of procedure, are spoken of as _causes_ of the events which conform to them, no account being taken of the Active Power that is ultimately responsible for the rules. For the Active Power in which we live, move, and have our being, is not a datum of sense; meditation brings it into light. But to pursue this thought would carry us beyond the physical laws of Motion (sect. 69-72).

The _De Motu_ may be compared with what we found in the _Principles_, sect. 25-28 and 101-117. The total powerlessness of the significant appearances presented to the senses, and the omnipotence of Mind in the economy of external nature, is its chief philosophical lesson.

De Motu

1. Ad veritatem inveniendam præcipuum est cavisse ne voces males intellectæ(925) nobis officiant: quod omnes fere monent philosophi, pauci observant. Quanquam id quidem haud adeo difficile videtur, in rebus præsertim physicis tractandis, ubi locum habent sensus, experientia, et ratiocinium geometricum. Seposito igitur, quantum licet, omni præjudicio, tam a loquendi consuetudine quam a philosphorum auctoritate nato, ipsa rerum natura diligenter inspicienda. Neque enim cujusquam auctoritatem usque adeo valere oportet, ut verba ejus et voces in pretio sint, dummodo nihil clari et certi iis subesse comperiatur.

‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐

2. Motus contemplatio mire torsit veterum philosophorum(926) mentes, unde natæ sunt variæ opiniones supra modem difficiles, ne dicam absurdæ; quæ, quum jam fere in desuetudinem abierint, haud merentur ut iis discutiendis nimio studio immoremur. Apud recentiores autem et saniores hujus ævi philosophos(927), ubi de Motu agitur, vocabula haud pauca abstractæ nimium et obscuræ significationis occurrunt, cujusmodi sunt _solicitatio gravitatis_, _conatus_, _vires mortuæ_, &c., quæ scriptis, alioqui doctissimis, tenebras offundunt, sententiisque non minus a vero, quam a sensu hominum communi abhorrentibus, ortum præbent. Hæc vero necesse est ut, veritatis gratia, non alios refellendi studio, accurate discutiantur.

3. _Solicitatio_ et _nisus_, sive _conatus_, rebus solummodo animatis revera competunt(928). Cum aliis rebus tribuuntur, sensu metaphorico accipiantur necesse est. A metaphoris autem abstinendum philosopho. Porro, seclusa omni tarn animæ affectione quam corporis motione, nihil clari ac distincti iis vocibus significari, cuilibet constabit qui modo rem serio perpenderit.

4. Quamdiu corpora gravia a nobis sustinentur, sentimus in nobismet ipsis nisum, fatigationem, et molestiam. Percipimus etiam in gravibus cadentibus motum acceleratum versus centrum telluris; ope sensuum præterea nihil. Ratione tamen colligitur causam esse aliquam vel principium horum phænomenon; illud autem _gravitas_ vulgo nuncupatur. Quoniam vero causa descensus gravium cæca sit et incognita, gravitas ea acceptione proprie dici nequit qualitas sensibilis; est igitur qualitas occulta. Sed vix, et ne vix quidem, concipere licet quid sit qualitas occulta, aut qua ratione qualitas ulla agere aut operari quidquam possit. Melius itaque foret, si, missa qualitate occulta, homines attenderent solummodo ad effectus sensibiles; vocibusque abstractis (quantumvis illæ ad disserendum utiles sint) in meditatione omissis, mens in particularibus et concretis, hoc est in ipsis rebus, defigeretur.

5. _Vis_(929) similiter corporibus tribuitur: usurpatur autem vocabulum illud, tanquam significaret qualitatem cognitam, distinctamque tarn a motu, figura, omnique alia re sensibili, quam ab omni animalis affectione: id vero nihil aliud esse quam qualitatem _occultam_, rem acrius rimanti constabit. Nisus animalis et motus corporeus vulgo spectantur tanquam symptomata et mensuræ hujus qualitatis occultæ.

6. Patet igitur gravitatem aut vim frustra poni pro principio(930) motus: nunquid enim principium illud clarius cognosci potest ex eo quod dicatur qualitas occulta? Quod ipsum occultum est, nihil explicat: ut omittamus causam agentem incognitam rectius dici posse substantiam quam qualitatem. Porro _vis_, _gravitas_, et istiusmodi voces, sæpius, nec inepte, in concreto usurpantur; ita ut connotent corpus motum, difficultatem resistendi, &c. Ubi vero a philosophis adhibentur ad significandas naturas quasdam, ab hisce omnibus præcisas et abstractas, quæ nec sensibus subjiciuntur, nec ulla mentis vi intelligi nec imaginatione effingi(931) possunt, turn demum errores et confusionem pariunt.

7. Multos autem in errorem ducit, quod voces generales et abstractas in disserendo utiles esse videant, nec tamen earum vim satis capiant. Partim vero a consuetudine vulgari inventæ sunt illæ ad sermonem abbreviandum, partim a philosophis ad docendum excogitatæ; non quod ad naturas rerum accommodatas sint, quæ quidem singulares et concretæ existunt; sed quod idoneæ ad tradendas disciplinas, propterea quod faciant notiones, vel saltem propositiones, universales(932).