Reversibility

“ If we divide an irreversible process into its elementary constituents, the disorder and along with it the irreversibility vanishes; an irreversible process must remain beyond the understanding of anyone who relies upon the fundamental law: that all properties of the whole must also be recognizable in the parts. ”

“ Now after all the irreversibility in nature thus appears in a certain sense eliminated, it is an illuminating fact that general elementary dynamics has only to do with reversible processes. Therefore we shall occupy ourselves in what follows with reversible processes exclusively. That which makes this procedure so valuable for the theory is the circumstance that all known reversible processes, be they mechanical, electrodynamical or thermal, may be brought together under a single principle which answers unambiguously all questions regarding their behavior. ”

“ It is evident then that the only means to assure to the second law real meaning consists in this, that the idea of irreversibility be made independent of any relationship to man and especially of all technical relations. ”

“ On the contrary: mankind is making every endeavor to press beyond the present boundaries of its capacity, and we hope that later on many things will be attained which, perhaps, many regard at present as impossible of accomplishment. Can it not happen then that a process, which up to the present has been regarded as irreversible, may be proved, through a new discovery or invention, to be reversible? In this case the whole structure of the second law would undeniably collapse, for the irreversibility of a single process conditions that of all the others. ”

“ A reversible process we have declared to be only an ideal case, a convenient and fruitful fiction which we can imagine by eliminating from an irreversible process one or more of its inevitable accompaniments like friction or heat conduction. ”

“ If we could imagine the mechanism of the world to consist only of reversible processes, and that at a given instant the motions of all the particles of matter were reversed as a ball is knocked back, then the history of the material world would play itself over again backward. ”

“ All existence or all effect is produced in equilibrium, that is, by one force acting and another suffering itself to be acted upon, or when one force by acting flows in, the other receives and harmoniously submits. ”

“ Something tells us that all this is provisional; that the weakened reasons will wax strong again, and the stronger weaken; that equilibrium is unreached; that testing our reasons, not obeying them, is still the order of the day, and that we must wait awhile, patient or impatiently, until our mind is made up 'for good and all.' This inclining, first to one then to another future, both of which we represent as possible, resembles the oscillations to and fro of a material body within the limits of its elasticity. ”

“ Either complete equilibrium must in itself be an impossibility, or the changes of energy introduce themselves in the circular process before that equilibrium which is in itself possible has appeared.—But it would be madness to ascribe a feeling of self-preservation to existence! ”

“ An act of volition, whether followed by an effect or not, is accompanied by a consciousness of effort, “of force exerted, of power in action, which is necessarily causal, or causative.” This feeling of energy or force, inherent in an act of will, is knowledge à priori; assurance, prior to experience, that we have the power of causing effects. Volition, therefore, [pg 361] it is asserted, is something more than an unconditional antecedent; it is a cause, in a different sense from that in which physical phenomena are said to cause one another: it is an Efficient Cause. ”

“ With hands clenched in the shade and tears of gall,
When Vengeance beats her hellish battle-call,
And makes herself the captain of our fate,
Angel of kindness, have you tasted hate?
Angel of health, did ever you know pain,
Which like an exile trails his tired footfalls
The cold length of the white infirmary walls,
With lips compressed, seeking the sun in vain? ”

“ Such a process is called a reversible process, for the reason that the fluid will pass through the same series of states in reverse order if the external influences are changed slowly in reverse sense. ”

“ Those who are subject to the state called reverie, feel as if their nature were dissolved into the surrounding universe, or as if the surrounding universe were absorbed into their being. They are conscious of no distinction. And these are states which precede, or accompany, or follow an unusually intense and vivid apprehension of life. As men grow up this power commonly decays, and they become mechanical and habitual agents. Thus feelings and then reasonings are the combined result of a multitude of entangled thoughts, and of a series of what are called impressions, planted by reiteration. ”

“ But as a reversible process is the only one which can maintain itself for all time, it follows that our earth is gradually lowering its energy from high to lower classes; the ultimate form to which all must be reduced being that which has its source not in the position or motion of masses, but of molecules. ”

“ The changes of which science has at length caught a glimpse can be nothing more than the regular and cyclical or fitful and spasmodic disturbances of a deeper and universal state of forced equilibrium, which pervades the vital as it is known to pervade the mechanical world. ”

“ We saw that to assume an identity of nature between the cause of changes as it absolutely exists, and that cause of change of which we are conscious in our own muscular efforts, betrays us into alternative impossibilities of thought. Force, as we know it, can be regarded only as a certain conditioned effect of the Unconditioned Cause—as the relative reality indicating to us an Absolute Reality by which it is immediately produced. ”

“ If we should conceive, for example, that the human mind, with its different possibilities of equilibrium, might be like a many-sided solid with different surfaces on which it could lie flat, we might liken mental revolutions to the spatial revolutions of such a body. ”

“ He would not limit the negative movement to one act or to one point in time; the movement towards a higher world must be maintained—the sustaining of the negative movement being a test of the reality of conversion. The process of conversion is not a process to be passively undergone, or to originate from without, but is a movement starting in the depths of one's own being. ”

“ The admission that not all, but only every deep-seated physiological detailed modification, is or may be bound up with a system of correlated changes, indeed implies that we on our side also acknowledge an internal harmony of parts—an equilibrium, as I have above expressed it. ”

“ The characteristic required in addition to continuity is conformity with the laws of dynamics. Starting from what common sense regards as persistent things, and making only such modifications as from time to time seem reasonable, we arrive at assemblages of "sensibilia" which are found to obey certain simple laws, namely those of dynamics. By regarding "sensibilia" at different times as belonging to the same piece of matter, we are able to define motion, which presupposes the assumption [172] or construction of something persisting throughout the time of the motion. ”

“ Of course we are: but there is a universal balance throughout nature, and everything finds its level. There is order, when there appears disorder—and no stream runs in one direction, without a counter stream, to restore the equilibrium. ”

“ This element is our feeling of succession, or time—a feeling, which necessarily, involves the notion of divisibility or series of parts, that is so essential a constituent of our more complex notion of matter,—and to which notion of continuous divisibility, if the notion of resistance be added, it is scarcely possible for us to imagine, that we should not have acquired, by this union, the very notion of physical extension,—that which has parts, and that which resists our effort to grasp it. ”

“ Tendency to equilibrium of force and to permanency of form then, are the characters of that portion of the universe which does not live—the domain of the chemist and physicist.
Tendency to disturb existing equilibrium,—to take on forms which succeed one another in definite cycles, is the character of the living world. ”

“ By this mutual transfusion an equilibrium is preserved, like that which similar processes maintain in the natural world, and while a healthy, popular feeling circulates through the Aristocracy, a sense of their own station in the scale elevates the People. ”

“ The physical occasion enters into the mental occasion, as already actual, and as contributing to its ground. The reversion from its ground, which the consequent of ideal novelty must exhibit, is now of the most fundamental character. The reversion is the undoing of the synthesis exhibited in the ground. Thus the transition from bodily occasion to mental occasion exhibits a new dimension of transition from that exhibited in the transition from bodily occasion to bodily occasion. In the latter transition there is the novelty of contrast within the one concept of synthesis. ”

“ That the cause must precede the effect,—that the effect must follow the cause,—are, it might seem, self-evident truths, assumed and assented to by all persons in all reasonings in which those notions occur. Such a doctrine is commonly asserted in general terms, and seems to be verified in all the applications of the idea of cause. A heavy body produces motion by its weight; the motion produced is subsequent in time to the pressure which the weight exerts. ”

“ They interact and develop each other without end; for each action of E upon O changes O, whose reaction in turn upon ·E changes E, so that E's new action upon O gets different, eliciting a new reaction, and so on indefinitely. The situation gets perpetually 'reconstructed,' to use another of Professor Dewey's favorite words, and this reconstruction is the process of which all reality consists. ”

“ And to each is appointed a fixed term of existence. Sooner or later, the balance of equilibrium is tilted, disturbance eventuates in overthrow; the tiny exquisite system finally breaks up. Of atoms, as of men, it may be said with truth, "Quisque suos patitur manes." ”

“ It is a corollary that when the environment is changed, the equilibrium of functions is disturbed, and there must follow one of two results—either the equilibrium is overthrown or it is re-adjusted: there is a re-equilibration. ”

“ In these examples the changes are obtrusive and easily observed, and by meditating on these examples, I think you may bring yourselves to understand something of the doctrine of Being and not-Being, as inseparably united in Becoming. You are not, however, to suppose that in cases where the changes are not thus apparent, no changes are taking place. The process may often be imperceptible; yet I believe that change is continually going on everywhere, and in every particle in the universe. ”

“ Every thing which is called arising and departing, every change rests therefore only upon the mingling and withdrawing of these eternal and fundamental materials; the inexhaustible manifoldness of being rests upon the different proportions in which these elements are mingled. Every becoming is conceived as such only as a change of place. In this we have a mechanical in opposition to a dynamic explanation of nature.
3. The Two Powers.—Whence now can arise any becoming, if in matter itself there is found no principle to account for the change? ”

“ In this conception the identity of a supposed agent or force is evidently sustained in thought. Struck by the definite proportionality found to obtain between the changes occurring simultaneously in the substratum from which the force is thought to have been transferred, and the substratum to which it is thought to have been transferred, the mind is induced by means of a fictitious entity substantially to connect the changes as such, losing sight of the true substances, of which the changes are in reality mere affections. ”

“ The reason why it is thought that physical processes give rise to mental, lies in the fallacious analogy taken from the law of convertibility and equivalence of energy in the activity of physical processes. ”

“ As we proceed further and further from the time at which alternative actions are open to us, the events of which either action would be part cause become increasingly dependent on those other circumstances, which are the same, whichever action we adopt. The effects of any individual action seem, after a sufficient space of time, to be found only in trifling modifications spread over a very wide area, whereas its immediate effects consist in some prominent modification of a comparatively narrow area. ”

“ If it is a mechanical force, then the immediate effect is some distortion of the part—a distortion having for its limit that attitude in which the resistance of the structures to further change of position, balances the force tending to produce the further change; and the ultimate effect, supposing the force to be continuous or recurrent, is such a permanent alteration of form, or alteration of structure, or both, as establishes a permanent balance. ”

“ But if, e.g., a material change of state can be the cause of a determination in God, the whole basis of the denial that a change in the material order can originate change in another order of reality, is swept away. ”

“ All change is revealed in the light of immediate intuition, not as a numerical series of states, but a rhythm of phases, each of which constitutes an indivisible act, in such a way that each change has its natural inner articulations, forbidding us to break it up according to arbitrary laws, like a homogeneous length. ”