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The disagreement of galileo and descartes with the theories and explanations of aristotle

References and Further Reading 1. The definition is a conjunction of two terms which normally contradict each other, along with, in Greek, a qualifying clause which seems to make the contradiction inescapable. Thomas Aquinas called it the only possible way to define motion by what is prior to and better known than motion. According to Descartes, "motion.

The use of the word "passes" makes this definition an obvious circle; Descartes might just as well have called motion the action by which a thing moves. But the important part of Descartes' definition is the words "nothing more than," by which he asserts that motion is susceptible of no definition which is not circular, as one might say "the color red is just the color red," to mean that the term is not reducible to some modification of a wave, or analyzable in any other way.

There must be ultimate terms of discourse, or there would be no definitions, and indeed no thought. The point is not that one cannot construct a non-circular definition of such a term, one claimed to be properly irreducible, but that one ought not to do so. The true atoms of discourse are those things which can be explained only by means of things less known than themselves. If motion is such an ultimate term, then to define it by means of anything but synonyms is willfully to choose to dwell in a realm of darkness, at the sacrifice of the understanding which is naturally the disagreement of galileo and descartes with the theories and explanations of aristotle in the form of "good sense" or ordinary common sense.

Descartes' treatment of motion is explicitly anti-Aristotelian and his definition of motion is deliberately circular. The Cartesian physics is rooted in a disagreement with Aristotle about what the best-known things are, and about where thought should take its beginnings.

There is, however, a long tradition of interpretation and translation of Aristotle's definition of motion, beginning at least five hundred years before Descartes and dominating discussions of Aristotle today, which seeks to have things both ways. An unusually clear instance of this attitude is found in the following sentence from a medieval Arabic commentary: Motion is an entelechy; motion is a transition.

The strangeness of the word "entelechy" masks the contradiction between these two claims. It is at the heart not only of his definition of motion, but of all his thought. Its meaning is the most knowable in itself of all possible objects of the intellect. There is no starting point from which we can descend to put together the cements of its meaning. The problem with this alternative is that the word "actuality" already belongs to the English language, and has a life of its own which seems to be at variance with the simple sense of being active.

By the actuality of a thing, we mean not its being-in-action but its being what it is. For example, there is a fish with an effective means of camouflage: When an actuality is attributed to that fish, completely at rest at the bottom of the ocean, we don't seem to be talking about any activity.

But according to Aristotle, to be something always means to be at work in a certain way. In the case of the fish at rest, its actuality is the activity of metabolism, the work by which it is constantly transforming material from its environment into parts of itself and losing material from itself into its environment, the activity by which the fish maintains itself as a fish and as just the fish it is, and which ceases only when the fish ceases to be.

Any static state which has any determinate character can only exist as the outcome of a continuous expenditure of effort, maintaining the state as it is. Thus even the rock, at rest next to the fish, is in activity: Nothing is which is not somehow in action, maintaining itself either as the whole it is, or as a part of some whole.

A rock is inorganic only when regarded in isolation from the universe as a whole which is an organized whole just as blood considered by itself could not be called alive yet is only blood insofar as it contributes to the maintenance of some organized body. No existing rock can fail to contribute to the hierarchical organization of the universe; we can therefore call any existing rock an actual rock. Energeia, then, always means the being-at-work of some definite, specific something; the rock cannot undergo metabolism, and once the fish does no more than fall to earth and remain there it is no longer a fish.

The material and organization of a thing determine a specific capacity or potentiality for activity with respect to which the corresponding activity has the character of an end telos. Endelecheia means continuity or persistence. The use of the pun for the serious philosophic purpose of saying at once two things for whose union the language has no word was a frequent literary device of Aristotle's teacher Plato.

In this striking instance, Aristotle seems to have imitated the playful style of his teacher in constructing the most important term in his technical vocabulary.

Entelecheia means continuing in a state of completeness, or being at an end which is of such a nature that it is only possible to be there by means of the continual expenditure of the effort required to stay there. The word actuality as thus used is very close in meaning to the word life, with the exception that it is broader in meaning, carrying no necessary implication of mortality.

The answer is now obviously "no. A dog is not a puppy: We might have trouble deciding exactly when the puppy has ceased to be a puppy and become a dog at the age of one year, for example, it will probably be fully grown and capable of reproducing, but still awkward in its movements and puppyish in its attitudes, but in any respect in which it has become a dog it has ceased to be a puppy.

But our concern was to understand what motion is, and it is obviously the puppy which is in motion, since it is growing toward maturity, while the dog is not in motion in that respect, since its activity has ceased to produce change and become wholly directed toward self-maintenance. It seems that Descartes is right and Aristotle is wrong.

Now, this suggestion would be laughable if it were not what almost everyone who addresses the question today believes. Sir David Ross, certainly the most massively qualified authority on Aristotle of those who have lived in our century and written in our language, the man who supervised the Oxford University Press's forty-five year project of translating all the works of Aristotle into English, in a commentary, on Aristotle's definition of motion, writes: It is not translation or interpretation but plastic surgery.

Ross' full account of motion as actualization Aristotle, New York, 1966, pp. There are authorities he could have cited, including Moses Maimonides, the twelfth century Jewish philosopher who sought to reconcile Aristotle's philosophy with the Old Testament and Talmud, and who defined motion as "the transition from potentiality to actuality," and the most famous Aristotelian commentator of all time, Averroes, the twelfth century Spanish Muslim thinker, who called motion a passage from non-being to actuality and complete reality.

In each case the circular definition is chosen in preference to the one which seems laden with contradictions. A circular statement, to the extent that it is circular, is at least not false, and can as a whole have some content: Descartes' definition amounts to saying "whatever motion is, it is possible only with respect to place," and that of Averroes, Maimonides, and Ross amounts to saying "whatever motion is, it results always in an actuality.

There has been one major commentator on Aristotle who was prepared to take seriously and to make sense of both these claims. Thomas Aquinas, in his interpretation of Aristotle's definition of motion, Commentary on Aristotle's Physics, London, 1963, pp.

Writing a century after Maimonides and Averroes, Thomas disposes of their approach to defining motion with few words: A passage, a transition, an actualization, an actualizing, or any of the more complex substantives to which translators have the disagreement of galileo and descartes with the theories and explanations of aristotle which incorporate in some more or less disguised form some progressive sense united to the meaning of actuality, all have in common that they denote a kind of motion.

If motion can be defined, then to rest content with explaining motion as a kind of motion is certainly to err; even if one is to reject Aristotle's definition on fundamental philosophical grounds, as Descartes was to do, the first step must be to see what it means.

Aristotle: Motion and its Place in Nature

And Thomas explains clearly and simply a sense in which Aristotle's definition is both free of contradiction and genuinely a definition of motion. What else do we mean by saying that the puppy is growing, rather than remaining what it is, that the bronze under the sculptor's hand is in a different condition from the identically shaped lump of bronze he has discarded, or that the water is not just tepid but being heated?

Motion is the mode in which the future belongs to the present, is the present absence of just those particular absent things which are about to be. Thomas discusses in detail the example of the water being heated. Assume it to have started cold, and to have been heated so far to room temperature.

The heat it now has, which has replaced the potentiality it previously had to be just that hot, belongs to it in actuality. The capacity it has to be still hotter belongs to it in potentiality. To the extent that it is actually hot it has been moved; to the extent that it is not yet as hot as it is going to be, it is not yet moved.

In Thomas' version of Aristotle's definition one can see the alternative to Descartes' approach to physics.

  • To warrant this judgment, something that does not change must have been perceived in the wax;
  • If the river flows, how can it continue to be itself?
  • Aristotle vs plato comparison aristotle and plato were philosophers in ancient greece aristotle, augustine, neoplatonism, cicero, plutarch, stoicism, anselm, descartes, hobbes, leibniz, mill, schopenhauer for an example of theory espoused by aristotle and plato that is no;
  • But the condemnation of Galileo by the Inquisition for maintaining this latter thesis led Descartes to suppress its publication.

Since Descartes regards motion as ultimate and given, his physics will give no account of motion itself, but describe the transient static configurations through which the moving things pass. By Thomas' account, motion is not ultimate but is a consequence of the way in which present states of things are ordered toward other actualities which do not belong to them.

One could build on such an account a physics of forces, that is, of those directed potentialities which cause a thing to move, to pass over from the actuality it possesses to another which it lacks but to which it is ordered. Motion will thus not have to be understood as the mysterious departure of things from rest, which alone can be described, but as the outcome of the action upon one another of divergent and conflicting innate tendencies of things.

Rest will be the anomaly, since things will be understood as so constituted by nature as to pass over of themselves into certain states of activity, but states of rest will be explainable as dynamic states of balance among things with opposed tendencies.

Leibniz, who criticized Descartes' physics and invented a science of dynamics, explicitly acknowledged his debt to Aristotle see, e.

From Leibniz we derive our current notions of potential and kinetic energy, whose very names, pointing to the actuality which is potential and the actuality which is motion, preserve the Thomistic resolutions of the two paradoxes in Aristotle's definition of motion.

Thomas' discussion of motion, it can be seen also to reveal difficulties in Thomas' conclusions.

  1. Moreover, even if no route seems most probable, some route must be chosen and resolutely acted upon and treated as the most true and certain.
  2. Assume it to have started cold, and to have been heated so far to room temperature. Geometrical ideas are paradigm examples of innate ideas.
  3. Hence, if this problem cannot be resolved, then it could be used to imply that mind and body are not completely different but they must have something in common in order to facilitate this interaction. The other two parts were to be on plant and animal life and on human beings, but he decided it would be impossible for him to conduct all the experiments necessary for writing them.
  4. Princeton University Press, 2003. Whatever that might mean, it could at any rate not be a definition of motion.

According to Thomas, actuality and potentiality do not exclude one another but co-exist as motion. To the extent that an actuality is also a potentiality it is a motion, and to the extent that an actuality is a motion it is a potentiality. The two seeming contradictions cancel each other in the dynamic actuality of the present state which is determined by its own future. But are not potential and kinetic energy two different things?

A rock held six feet above the ground has been actually moved identically to the rock thrown six feet above the ground, and at that distance each strains identically to fall to earth; but the one is falling and the other isn't.

The disagreement of galileo and descartes with the theories and explanations of aristotle

How can the description which is common to both, when one is moving and the other is at rest, be an account of what motion is? It seems that everything which Thomas says about the tepid water which is being heated can be said also of the tepid water which has been removed from the fire. Each is a coincidence of a certain actuality of heat with a further potentiality to the same heat. What does it mean to say that the water on the fire has, right now, an order to further heat which the water off the fire lacks?

If we say that the fire is acting on the one and not on the other in such a way as to disturb its present state, we have begged the question and returned to the position of presupposing motion to explain motion. Thomas' account of Aristotle's definition of motion, though immeasurably superior to that of Sir David Ross as interpretation, and far more sophisticated as an approach to and specification of the conditions an account of motion would have to meet, seems ultimately subject to the same circularity.

René Descartes (1596—1650)

Maimonides, Averroes, and Ross fail to say how motion differs from rest. Thomas fails to say how any given motion differs from a corresponding state of balanced tension, or of strain and constraint. The strength of Thomas' interpretation of the definition of motion comes from his taking every word seriously. By Thomas' account, motion is the actuality of any potentiality which is nevertheless still a potentiality.

It is the actuality which has not canceled its corresponding potentiality but exists along with it. Motion then is the actuality of any potentiality insofar as it is still a potentiality.

This is the formula which applies equally well to the dynamic state of rest and the dynamic state of motion. If the clause is understood adverbially, then, the sentence must mean something like: Whatever that might mean, it could at any rate not be a definition of motion.

Thus the clause must be understood adjectivally, and Thomas must make the relative pronoun dependent upon a word with which it does not agree in gender.

He makes the sentence say that motion is the actuality of the potentiality in which there is yet potentiality. The beginning of this entry says that Aristotle's definition of motion was made by putting together two terms, actuality and potentiality, which normally contradict each other. Thomas resolved the contradiction by arguing that in every motion actuality and potentiality are mixed or blended, that the condition of becoming-hot of the water is just the simultaneous presence in the same water of some actuality of heat and some remaining potentiality of heat.

Earlier it was stated that there was a qualifying clause in Aristotle's definition which seemed to intensify, rather than relieve, the contradiction. The Thomistic blend of actuality and potentiality has the characteristic that, to the extent that it is actual it is not potential and to the extent that the disagreement of galileo and descartes with the theories and explanations of aristotle is potential it is not actual; the hotter the water is, the less is it potentially hot, and the cooler it is, the less is it actually, the more potentially, hot.

Aristotle's definition of motion applies to any and every motion:

  1. But how can two substances with completely different natures causally interact?
  2. The third general law of motion, in turn, governs the collision and deflection of bodies in motion.
  3. But how can a stone know anything, since it does not think? Here judgment is described as a faculty of the mind resulting from the interaction of the faculties of intellect and will.
  4. The material and organization of a thing determine a specific capacity or potentiality for activity with respect to which the corresponding activity has the character of an end telos. Different copernican theories certainly offered explanations of but how did simplicity influence this argument like galileo, descartes did link simple to the copernican wilson db 2011 simplicity in the copernican revolution.
  5. Here judgment is described as a faculty of the mind resulting from the interaction of the faculties of intellect and will. References and Further Reading 1.