Physics by Aristotle

Physics Reviews

• 
  Orhan Pelinkovic

  "The proper analogy might be that Zeus does not send rain so that the crops will grow: it is just a matter of necessity."
  
  Physics is Aristotle's (384-322 BCE) philosophy of nature. Aristotle ponders why are things in nature the way they are? Why do living and non-living things in nature behave the way they do? Aristotle, employs his four causes in order to answer these questions. Therefore, the four ways we can explain a 'thing' is through; its material composition, the basic nature of the thing, its source of change and rest, and the things aim and purpose.
  
  As you can see, this is not a typical physics book, it's more of a philosophical take on the natural sciences. Although, the book ingeniously discusses infinity, continuity, place, space, time, and motion. Some of Aristotle's arguments reminded me of classical physics, the law of conservation of energy, the states of matter, and such descriptions of time associated me to entropy: "We do not say time has made him young"..."...time is responsible for destruction rather than for generation." The chapter on time has left a profound impression on me and the chapters on change a lasting impression on the physics world today.
  
  Aristotle, uses logic and observation to set the basic principles of the natural sciences, but does not implement experimentation, as this method was much later introduced, for deriving at scientific conclusions. Now, part of the arguments, Aristotle, arrives at are wrong, and he also has this urge to disprove the previous philosophers, especially Democritus and Zeno, which turns out by the current accepted knowledge, that Aristotle, was not completely right. But this does not diminish anything, as Aristotle, had a brilliant mind with which he arrived at revolutionary ideas. He is so capable of dissecting both the physical natures characteristics and his thoughts and turning them into logical expressions. He has a way with words. At times, it feels like he is playing with words or engaging in some type of logical and language arithmetic. But it's clear that this books topics and ideas were a source and inspiration for numerous scientists for millenniums to come.
  
  (4.5/5.0)
• 
  Roy Lotz

  Of all the ancient thinkers that medieval Christians could have embraced, it always struck me as pretty remarkable that Aristotle was chosen. Of course, ‘chosen’ isn’t the right word; rather, it was something of a historical coincidence, since Aristotle’s works were available in Latin translation, while those of Plato were not.
  
  Nonetheless, Aristotle strikes me as a particularly difficult thinker to build a monotheistic worldview around. There’s simply nothing mystical about him. His feet are planted firmly on the ground, and his eyes are level with the horizon. Whereas mystics see the unity of everything, Aristotle divides up the world into neat parcels, providing lists of definitions and categories wherever he turns. Whereas mystics tend to scorn human knowledge, Aristotle was apparently very optimistic about the potential reach of the human mind—since he so manifestly did his best to know everything.
  
  The only thing that I can find remotely mystical is Aristotle’s love of systems. Aristotle does not like loose ends; he wants his categories to be exhaustive, and his investigations complete. And, like a mystic, Aristotle is very confident about the reach of a priori knowledge, while his investigations of empirical reality—though admittedly impressive—are paltry in comparison with his penchant for logical deduction. At the very least, Aristotle is wont to draw many more conclusions from a limited set of observations than most moderns are comfortable with.
  
  I admit, in the past I’ve had a hard time appreciating his writing. His style was dry; his arguments, perfunctory. I often wondered: What did so many people see in him? His tremendous influence seemed absurd after one read his works. How could he have seemed so convincing for so long?
  
  I know from experience that when I find a respected author ludicrous, the fault is often my own. So, seeking a remedy, I decided that I would read more Aristotle; more specifically, I would read enough Aristotle until I learned to appreciate him. For overexposure can often engender a change of heart; in the words of Stephen Stills, “If you can’t be with the one you love, love the one you’re with.” So I decided I would stick with Aristotle until I loved him. I still don’t love Aristotle, but, after reading this book, I have a much deeper respect for the man. For this book really is remarkable.
  
  As Bertrand Russell pointed out (though it didn’t need a mind as penetrating as Russell’s to do so), hardly a sentence in this book can be accepted as accurate. In fact, from our point of view, Aristotle’s project was doomed from the start. He is investigating physical reality, but is doing so without conducting experiments; in other words, his method is purely deductive, starting from a few assumptions, most of which are wrong. Much of what Aristotle says might even seem silly—such as his dictum that “we always assume the presence in nature of the better.” Another great portion of this work is taken up by thoroughly uninteresting and unconvincing investigations, such as the definitions of ‘together’, ‘apart’, ‘touch’, ‘continuous’, and all of the different types of motions—all of which seem products of a pedantic brain rather than qualities of nature.
  
  But the good in this work far outweighs the bad. For Aristotle commences the first (at least, the first, so far as I know) intellectually rigorous investigations of the basic properties of nature—space, time, cause, motion, and the origins of the universe. I find Aristotle’s inquiry into time particularly fascinating, for I’m not aware—at least, I can’t recall—any comparatively meticulous investigations of time by later philosophers I've read. Of course, Aristotle’s investigation of ‘time’ can be more properly called Aristotle’s investigation of the human experience of time, but we need not fault Aristotle for not thinking there’s a difference.
  
  I was particularly impressed with Aristotle’s attempt to overcome Zeno’s paradoxes. He defines and re-defines time—struggling with how it can be divided, and with the exact nature of the present moment—and tries many different angles of attack. And what’s even more interesting is that Aristotle fails in his task, and even falls into Zeno’s intellectual trap by unwittingly accepting Zeno’s assumptions.
  
  Aristotle's attempts to tackle space were almost equally fascinating; for there, we once again see the magnificent mind of Aristotle struggling to define something of the highest degree of abstractness. In fact, I challenge anyone reading this to come up with a good definition of space. It's hard, right? The paradox (at least, the apparent paradox) is that space has some qualities of matter—extension, volume, dimensions—without having any mass. It seems, at first sight at least, like empty space should be simply nothing, yet space itself has certain definite qualities—and anything that has qualities is, by definition, something. However, these qualities only emerge when one imagines a thing in space, for we never, in our day to day lives, encounter space itself, devoid of all content. But how could something with no mass have the quality of extension?
  
  As is probably obvious by now, I am in no way a physicist—and, for that matter, neither was Aristotle; but his attempt is still interesting.
  
  Aristotle does also display an admirable—though perhaps naïve—tendency to trust experience. For his refutation of the thinkers who argue that (a) everything is always in motion, and (b) everything is always at rest, is merely to point out that day-to-day experience refutes this. And Aristotle at least knows—since it is so remarkably obvious to those with eyes—that Zeno must have committed some error; so even if his attacks on the paradoxes don’t succeed, one can at least praise the effort.
  
  To the student of modern physics, this book may present some interesting contrasts. We have learned, through painstaking experience, that the most productive questions to ask of nature begin with “how” rather than “why.” Of course, the two words are often interchangeable; but notice that “why” attributes a motive to something, whereas “how” is motiveless. Aristotle seeks to understand nature in the same way that one might understand a friend. In a word, he seeks teleological explanations. He assumes both that nature works with a purpose, and that the workings of nature are roughly accessible to common sense, with some logical rigor thrown in. A priori, this isn’t necessarily a bad assumption; in fact, it took a lot of time for us humans to realize it was incorrect. In any case, it must be admitted that Aristotle at least seeks to understand far more than us moderns; for Aristotle seeks, so to speak, to get inside the ‘mind’ of nature, understanding the purpose for everything, whereas modern scientific knowledge is primarily descriptive.
  
  Perhaps now I can see what the medieval Christians found in Aristotle. The assumption that nature works with a purpose certainly meshes well with the belief in an omnipotent creator God. And the assumption that knowledge is accessible through common sense and simple logical deductions is reasonable if one believes that the world was created for us. To the modern reader, the Physics might be far less impressive than to the medievals. But it is always worthwhile to witness the inner workings of such a brilliant mind; and, of all the Aristotle I’ve so far read, none so clearly show Aristotle’s thought process, none so clearly show his mind at work, as this.
• 
  Erick

  While this book helped me appreciate Aristotle's philosophical merit, it hasn't changed my opinion that Aristotle is tedious and pedantic.
  Aristotle does explore fascinating topics in this collection of lectures: infinity, time, change, place, movement/motion, space, etc, but Aristotle can make even topics that should be otherwise fascinating incredibly dry. Many of his arguments would seemingly require a diagrammatic approach, but, unfortunately, the reader is left to schematize Aristotle's logical constructions unaided. I personally did not labor over this aspect of his thought. Usually his points are understood intuitively without engaging in Aristotle's elaborate proofs. He does make some very salient points through out this book though and that made it worth reading.
  After reading his Metaphysics, I was curious as to Aristotle's approach to time and whether he considered it to be eternal; that he does indeed is made evident in this book. And as I said in my review to the Metaphysics, his prime mover has a rather perplexing relationship with time. While Aristotle denies infinity in most actual circumstances, he does consider time to be infinite. How a first mover can ever be reconciled to an infinite time is not at all clear. If he is within time, how could he have ever been the progenitor of a prime movement? It seems, as Aristotle declares, movement always existed in infinite time. If his prime mover exists outside of time, he must certainly be an ideal prime mover, but it still doesn't explain how he generates movement within infinite real time. Aristotle doesn't address these ambiguities here or in the Metaphysics.
  I had intended to go through more of Aristotle's writings after this, but as with what happened after reading his Metaphysics, I have had my fill of Aristotle for the time being.
• 
  Anmol

  This is a tough read, almost indecipherable in the first book, though I think it got better over time once I got used to it. Physics is a subject I have never particularly found attractive, though I have always been fascinated by space (astrophysics literature): hundreds of billions of exoplanets, the cosmic insignificance of our pale blue dot and everyone on it, yada yada. But I did appreciate Aristotle's attempt to investigate and reach definitions of all the major concepts of physics from first principles: particularly time, void, and motion. This definitely has some gems in here which are worth a read.
  
  I appreciate Aristotle's purposive theory of nature, though one wonders if it is really "purposive" or just natural selection at play. For example, he writes, in rare flowery prose -
  
  By gradual advance in this direction we come to see clearly that in plants too that is produced which is conducive to the end—leaves, e.g. grow to provide shade for the fruit. If then it is both by nature and for an end that the swallow makes its nest and the spider its web, and plants grow leaves for the sake of the fruit and send their roots down (not up) for the sake of nourishment, it is plain that this kind of cause is operative in things which come to be and are by nature.
  
  We now know, however, that nature and the universe altogether is a chaotic place, and it is highly improbable that there can be any purposiveness behind this chaos. Plants, animals, and ourselves have adapted, by natural selection, to this chaos. To me, this notion of purposiveness seems to go against the spirit of Aristotelian empiricism that follows. He maintains, however, that -
  
  It is absurd to suppose that purpose is not present because we do not observe the agent deliberating. Art does not deliberate. If the ship-building art were in the wood, it would produce the same results by nature. If, therefore, purpose is present in art, it is present also in nature. The best illustration is a doctor doctoring himself: nature is like that.
  
  This notion aside, I also like Aristotle's definition of time. He says -
  
  When, therefore, we perceive the ‘now’ as one, and neither as before and after in a motion nor as the same element but in relation to a ‘before’ and an ‘after’, no time is thought to have elapsed, because there has been no motion either. On the other hand, when we do perceive a ‘before’ and an ‘after’, then we say that there is time. For time is just this—number of motion in respect of ‘before’ and ‘after’. Hence time is not movement, but only movement in so far as it admits of enumeration.
  
  Or, for short, time exists for the one who looks at the clock (at least, this is my rudimentary interpretation of the possible implications of this passage). But in a later passage, time is defined slightly differently from my interpretation of the above passage:
  
  Time is not number with which we count, but the number of things which are counted; and this according as it occurs before or after is always different, for the ‘nows’ are different.
  
  My interpretation: the time is always now, but all nows differ from each other. So time is always changing, much like motion, but the "time" that we recognise is the motion that we have divided into convenient seconds, minutes, hours.
  
  In general, I like his usage of potentiality vs actuality. Motion, using these terms, becomes the actualisation of that which can potentially be moved: which I think is a solid definition.
  
  It continues to surprise me how much of a quantum leap Aristotle appears, at least on paper, from Plato. Plato has a literary skill which is great for newcomers to philosophy like myself. However, my qualm with his dialogues is that they are deceptively simple. One can finish reading them easily but might not get much out of them without reading interpretations, essays, etc. With Aristotle, I get everything I can out of the text by just reading it (slowly! something that I need to work on), because he doesn't hold anything back.
  
  
• 
  Tyler

  Finally I have finished this book. Due to work, I have not been able to read the last chapter for a long time now.
  
  This book is incredible. The ideas of derivatives, acceleration, kinetic and potential energy, everything is here described in immaculate detail. You can find the foundation here for most scientific developments and understanding about the universe, you can even find some immutable truths which never change.
  
  You will, surprisingly, find very little things that aren't true. Regardless of your position on a God, you must admit that the unmoved mover cannot be untrue. And in this case, the entire basis of the book, with a good foundation for various different disciplines, they have lended their minds greatly to what would eventually be a necessary influence, and movement, if you will, on academic learning in general.
  
  Indeed, like many other Aristotleian works, the ideas of physics, although they apply to the reality we live in, like many other authors (Witelo, Roger Bacon, and many other polymaths) these authors understood that movements, things that affect the physical reality, to have ramifications and symmetry in the moral sphere. This is directly referenced in the book itself, heightening the meaning of reading it.
  
  It is a vastly underrated work, simply because it is in the subject of 'science' and is an old book. There are immutable concepts which will never, and can't ever change, that textbooks will describe in detail in this book. You should read it, because you should understand the basis of their arguments and how little we have even progressed since those times.
• 
  kaelan

  First off, this is an exceedingly difficult text to get through. Although Aristotle is one of philosophy’s most brilliant minds, he is absolutely unquestionably wrong a lot of the time. What this means for the reader is that you have to be constantly critical—you can’t assume, for instance, that a particular argument is going to be valid or invalid... you actually have to get down to the logic of it and figure that s--t out.
  
  To confuse matters further, Aristotle will often introduce an apparently erroneous premise that, when looked at closely, proves to be unessential to the argument. So to reiterate: a passive reader will have a bad time with Physics—it is a struggle to even uncover what his arguments are the first place!
  
  That being said, Physics is an integral piece of philosophy for two main reasons: 1) disregarding his proposed solutions, the problems raised by Aristotle in this book are ones that have preoccupied philosophers ever since—as such, it is valuable for those interested in understanding later philosophy; and 2) the book does, in fact, contain some shining insights (see, for instance, Aristotle’s ingenious account of time—Book IV.11-14).
  
  The Oxford Classics text—translated by Robin Waterfield, with notes by David Bostock—is a solid edition; I couldn’t even fathom getting through this book without Bostock’s shrewd explanations helping me along.
  
• 
  Paul Haspel

  Physics, the study of the most basic properties of matter and energy, has always been an intimidating topic for me. I listen to physicists talk about how matter moves through space and time, or to their discussions of related concepts like force, and I often feel lost. Yet I know how important the ideas of physics and the work of physicists are – for through their studies, physicists seek to understand how the Universe itself works. For this reason, I turned with a mixture of trepidation and hope to Aristotle’s Physics, and was pleasantly surprised to find the treatise interesting and accessible.
  
  I appreciate how systematic Aristotle always is about setting forth his terms at the beginning of a treatise, describing exactly how he plans to break things down in his analysis of an area of inquiry. In just this manner, Aristotle states at the beginning of the Physics that “we do not think that we know a thing until we are acquainted with its primary conditions or first principles, and have carried our analysis as far as its simplest elements.”
  
  Aristotle begins by interrogating the nature of existence itself, writing that “Of things that exist, some exist by nature, some from other causes. ‘By nature’ the animals and their parts exist, and the plants and the simple bodies (earth, fire, air, water) – for we say that these and the like exist ‘by nature.’” He later adds that “Nature belongs to the class of causes that act for the sake of something”; and when he begins to discuss the concept of “necessity” in nature, one senses the beginning of the discussion of the concept of natural law – a law that is ordained by nature itself, that is absolute and unbreakable, and that pre-dates any law made by human beings. This concept, so important within the field of physics, has of course taken hold in other fields as well, being applied in a religious sense by theologians like Albertus Magnus and Thomas Aquinas, and in a political sense by political philosophers like Thomas Hobbes.
  
  Aristotle’s initial focus on motion leads to a discussion of the infinite. “The infinite,” Aristotle says, in a surprising turn, “turns out to be the contrary of what it is said to be. It is not what has nothing outside it that is infinite, but what always has something outside it.” More specifically, Aristotle states that “A quantity is infinite if it is such that we can always take a part outside what has already been taken.” He then goes on to apply these ideas to the concepts of time and magnitude, asserting that “Time…and movement are infinite, and also thinking, in the sense that each part that is taken passes in succession out of existence”, and, by contrast, that “Magnitude is not infinite either in the way of reduction or of magnification in thought.”
  
  I found this focus on the infinite most interesting. We’ve all seen the infinity symbol (∞); many of us, as small children, may have tried to win an argument by saying “Infinity!” or “Double infinity!” or “Double infinity plus one!” And any reader of science-fiction pulp magazines has read some variation on the story where the plucky human hero outwits the arrogant, world-conquering computer antagonist by challenging it to “find the ultimate number”; the hapless machine desperately adds and multiplies ever larger numbers, endlessly, until it breaks down or explodes, and humanity is saved, all because of infinity. Hurrah!
  
  But thinking in depth about the concept of infinity is truly much more challenging than any of that. The Universe, for instance, is said to be infinite, but with a finite age – a paradox worthy of the koans of Zen Buddhism. Additionally, the Universe is described as expanding – yet not as expanding into something “beyond” itself, but rather as expanding intrinsically, with the scale of space itself changing. These ideas are as challenging as they are important.
  
  From motion, Aristotle goes on to consider Place in regard to nature. There seems to be an element of relativity (so to speak) in Aristotle’s consideration of place; he relates the concept of place to the four classical elements, as when he writes that “It is not every chance direction which is ‘up,’ but where fire and what is light are carried; similarly, too, ‘down’ is not any chance direction but where what has weight and what is made of earth are carried – the implication being that these places do not differ merely in relative position, but also as possessing distinct potencies.”
  
  Aristotle is also interested in how time relates to motion – “For time is just this – number of motion in respect of ‘before’ and ‘after.’” He later adds that time “is continuous since it is an attribute of what is continuous.” He later asks, “Will time then fail? Surely not, if motion always exists. Is time then always different, or does the same time recur? Clearly time is, in the same way as motion is.” Nowadays, we talk about time as a fourth dimension, in terms of a space-time continuum; but the question of whether time had a beginning, or will have an end, is a question that brings together the speculations of physicists and of philosophers.
  
  Later, Aristotle discusses the nature of change – what it means when something changes. In the process, he explores the differences in meaning and implication among the terms “continuous,” “in contact,” and “in succession” Consider the points on a line: Are those points continuous, or are they in contact, or do they merely succeed upon one another? The question gets even more complicated in terms of Aristotle’s declaration that “every magnitude is divisible into magnitudes”. It then comes to seem that there no points on a line that are so precisely delineated that there can’t be points in between, on an even smaller magnitude.
  
  This is heavy stuff, clearly – and Aristotle likes to keep his discussion on the “purest” and most abstract level possible. For that reason, I found that I was most grateful when Aristotle would use a specific, “down-to-Earth” example to elucidate an abstract concept. To explain, for instance, his idea that “a thing that is in motion from one place to another cannot at the moment when it was in motion both be in motion and at the same time have completed its motion at the place to which it was in motion”, Aristotle provides this illustration: [I]f a man is walking to Thebes, he cannot be walking to Thebes and at the same time have completed his walk to Thebes”. More examples of that kind would have been welcome.
  
  In his discussion of motion, Aristotle states that when it comes to motion, “there must be three things – the moved, the movent, and the instrument of motion.” The requirement of a movent (meaning anything that moves or causes motion) applies even in the case of locomotion, where it might ordinarily be assumed that an animal, for example, might be causing itself to move. Truly, that concept of the movent is key to Aristotle’s ideas regarding motion. When it comes to circular motion like that of the planets – in Aristotle’s system, the only true continuous motion, since motion back and forth along a line necessarily involves some degree of stopping and starting – Aristotle states that in the case of circular or spherical motion, “the movent must occupy either the centre or the circumference, since these are the first principles from which a sphere is derived.”
  
  It is at this point that the Physics becomes once again a treatise that might be as interesting to theologians and philosophers as it already is to physicists – as Aristotle begins positing the existence of a “first movent” that “is indivisible and is without parts and without magnitude.” This concept is important in Aristotle’s system because of his belief that “there always was and always will be motion throughout time”, and his search for “the first principle of this eternal motion” leads him to the “primary motion…the only motion that can be eternal; and we have pronounced the first movent to be unmoved.” Elsewhere, Aristotle refers to this concept as a “First Principle.”
  
  That idea of the Greeks’ ὃ οὐ κινούμενον κινεῖ, or the Romans’ primum movens, or what we might call the “Unmoved Mover,” has been of great importance to many theologians. Thomas Aquinas, for example, made that concept of an “argument from first cause” the first of the Quinque Viae (Five Ways) through which he sought to provide logical proofs for the existence of God, as part of his Summa Theologica (1274). Everything has a cause, Aquinas reasons; and therefore, if one goes further and further back, from each cause to that cause’s own prior cause, one will eventually arise at the first cause before which there is no other cause – and in Aquinas’ system of reasoning, that first cause is, of course, God.
  
  However you feel about Aquinas’ interpretation of Aristotle’s idea of the “unmoved movent” or “First Principle,” we can all agree that – in physics, as in so many other areas of human inquiry – Aristotle established the conversation, setting down its basic premises in terms that the thinkers of later eras would find to be an eminently reasonable basis on which to develop their own hypotheses, devise their own experiments, evaluate their own results, and draw their own conclusions. As always, it is a pleasure to visit with Aristotle, bask in the brilliance of his rigorous intellect, and watch him begin the conversation.
  
• 
  Caspar Bryant

  Ok I got through it and I'm glad I read the Presocratics debrief beforehand I'd say that was pretty crucial. But Aristotle isn't exactly sexy so glad he's gone away until Metaphysics. CB was at A and got the F out of there
• 
  Xander

  Physics is a treatise by Aristotle in which he deals with the study of Nature, or rather, how we should study Nature. This comprises not just physics in the modern sense, but all things in the world - so to use modern phraseology Aristotle views the study of Nature to be the domain of physics, biology, even psychology.
  
  To understand the book, it is necessary to situatie Aristotle's treatise in the proper philosophical context. Aristotle was responding to his tutor Plato's conception of philosophy, as well as other contemporary and prior philosophers. His main adversaries are the Ionic natural philosophers claiming everything is change and plurality; the Eleatics claiming everything is unity and immutability; and the pluralists claiming simple immutable elements interact to combine changing pluralities. Aristotle's main strategy is roughly: (1) ask an interesting question, (2) see what others think about it, (3) criticize those views, and (4) then offer your own solution to the problem - with this approach he is the founder of analytical philosophy.
  
  The book itself is pretty straightforward, and one can argue that to understand Aristotle's conception of Nature (again including such fields as biology) it is necessary to read just the first three books and the last (eight) one.
  
  In book 1 he immediately cuts to the chase and claims that Nature is change, so the student of Nature should actually study change. And he almosti mmediately defines change as well: change is the acquisition of an attribute of a substance. Or in other terms: change is the process in which a thing moves from a state of privation to a final state in which it acquires its form. And with the notion of 'form' one of the three principles of Nature is introduced, the other two being 'matter' and 'privation'. Aristotle claims he can explain all change in terms of matter, form and privation.
  
  He distinguishes between two types of change: (1) the acquired form is an attribute in a category that's not substance, and (2) the acquired form is an attribute in the category of substance. The second type of change is problematic, since it seems to imply that in such a change some substance ceases to exist while at the same time some new substance is created out of nothing. Aristotle resolves this problem by claiming that matter might be the underlying substance of all primary substances (i.e. the four elements).
  
  In Book 2 Aristotle deals with an entirely different topic: the types of explanation a student of Nature should use. The relation of this topic to the content of Book 1 seems to be change, and this change is (literally) the nature of all things. To study nature, then, is to study how things behave - which itself is explained in terms of matter and form. The term 'behave' might seem to mislead people in tricking them to believe that things actually behave on their own accord. But the term is rather well-put, since Aristotle claims that coïncidence is not part of Nature, all natural things change according to four types of causes, which could be interpreted as these things having a 'will' (albeit it an unconscious one).
  
  Why four types of causes? Because, Aristotle claims, there are four types of questions a student of Nature should ask: (1) What is the thing made of? (2) What is its essence? (3) What effects the change? (4) What is the goal of this change? These questions respond to four causes: each thing has a (1) material cause, (2) a formal cause, (3) an efficient cause, and (4) a final cause. Once these four causes are explained, the behaviour of the thing is understood (at least physicially).
  
  So, what Aristotle seems to imply is that the study of Nature is the study of change, and that scientific explanations should answer all four questions about a natural thing, with the final cause as the most important element. Aristotle's conception of the universe is a craftsman, who molds matter in its designed form according to a pre-ordained purpose. Science should thus uncover Nature's intentions through studying the changes of natural objects.
  
  Then, in Book 3, he deals with change in more detail. According to Aristotle, change always happens through an act of an agent, through direct contact in which the actor impresses a form on the receiving object - and all change is localized in the receiving object. Further, he argues against the impossibility of an infinite universe (i.e. totality) but for the necessity of infinite time, magnitudes and numbers. This is a crucial argument: the totality of all matter cannot be infinite, yet when measuring any piece of matter there is the infinite divisibility of the thing in question. This stance cuts deep into the atomism of Democritus & co. who claimed that the entire universe consists of indivisible elementary particles (atoms), moving in a void.
  
  And speaking about a void, in Book 4 Aristotle argues that place does not exist apart from bodies (i.e. place is in the bodies, or rather is their continuous limit), and so a void is not only physically but moreover logically impossible. When matter compresses or expands, place expands with it - matter's potentiality actualizes and so matter increases or decreases without leaving behind or pushing away 'empty space'.
  
  Also in Book 4, Aristotle deals with time. According to him, time does not exist apart from change. Change is always the change of a thing (mostly movement of bodies), which can be expressed in numbers - this is what we call time. I have to admit that I find Aristotle's conception of time rather confusing and the entire chapter on time rather convoluted, so there's not much more I can make of it...
  
  In Book 5, Aristotle argues that change itself comes in three types: generation, destruction and variation - a subject either begins to exist, ceases to exist or changes an attribute. Further, variation can be split into alteration, increase/decrease and movement. Alteration always is concerned with the change of an attribute of a subject, never with the subject itself, this is because change is not substance, so it cannot have any attributes on its own. This, by the way, makes it impossible to explain phenomena like accelaration or decelaration, in which change is changing over time.
  
  Then, in Book 6, we learn about continuity. Starting from the assumption that movement is continuous (and not discrete), Aristotle concludes that time, space and matter are indivisible. While this allows Aristotle to dismantle Zeno's infamous paradoxes (about how a fast runner never can overtake a tortoise in a race, assuming a given distance), but it does contradict his earlier views on the infinity of time, magnitudes (and thus place) and numbers. And another problem is that when an object changes from movement to rest, these two cannot happen instanteneous, making rest impossible. This is an inconsistency in Aristotle's conception of continuity, and he opts for the solution to claim 'rest is no change'. Whether this is satisfying is another question.
  
  Book 7 offers some more notions on change, but the most important part is Book 8, in which Aristotle sets out his theory of the unmoved mover. He has claimed that change always happens through contact with an agent, which itself is changeable as well. Furthermore, he claimed that the force causing the change has to remain in effect, or else the object will move toward its natural place again. The problem is astronomy. When looking at the heavens, we see continuous, ever-changing bodies, so there has to be some agent (possibly more) forcing these bodies to move in the heavens.
  
  But if these agents itself require to be moved in order to move, we end up with an infinite regress of moving movers. To stop this regress, Aristotle postulates an unmoved mover - a being which can move things (how he doesn't explain) without needing any force to sustain itself. This makes this being infinitely powerful (in a physical sense) but this would mean it's immaterial, since anything material has a magnitude. So, we have a being which is infinitely powerful, immaterial, unchanging and this being is located just outside the outermost heavenly sphere carrying the fixed stars.
  
  And this concludes Physics. The book itself is rather a collection of treatises on different subjects, written in a very dense and abstract way, requiring lots of contextual information and familiarity with contemporary Greek philosophers. This makes the book rather unattractive and inaccessible, but it is certainly possible to distil some kind of narrative from all of the books. Aristotle's conception of the universe is (summarized):
  
  A collection of spherical shells, in which all the heavenly bodies, made of ether, follow their continuous circular and eternal paths through the heavens. In the sublunar world, everything is comprised of four elements - fire, air, water, and earth - which each have their natural place and have a tendency to seek out this natural place when displaced through force. In this sublunar region all movement is either natural (objects moving towards their natural place or in rest at this natural place) or unnatural (objects moving through the force applied by an agent). To understand the change in this sublunar sphere, one needs to study natural objects in terms of matter, form, impact and goal. The whole universe, thus, is teleological, following set goals.
  
  (If one thinks this makes Aristotle a determinist, one is wrong. For Aristotle claims that agents can initiate their own force and hence impact the world - in the Aristotelean world there is room for human freedom (or so it seems to me).)
  
  This is my first reading of Aristotle's original works - so take this review for what it's worth. I have read a lot of secundary information over the years, but since I have studied the Pre-Socratics and Plato, I felt the need to understand Aristotle as well, from his own materials. There seems to be no easy road into his philosophy - the most accessible works (on ethics and politics) are rather cut off from Aristotle's scientific and metaphysical thoughts, so starting with physics - a domain with which I felt quite familiar - seems to be a good idea. Next up: his logic, as epistemological preconditions for knowledge of nature. And once I grasp Aristotle's conception of Nature and his epistemology, perhaps I'll understand his metaphysics as well (I read somewhere that much of his metaphysics presupposes knowledge of his science and logic).
• 
  . ..

  ما قاله المترجم في هذه المقدمة : "
  ويتبين من هذه الأمثلة أن كتاب السماع الطبيعي أو الفيزياء الذي نقلب صفحاته، يشكل البنية الذهنية لكل قارئ عربي بها تنظم المعلومات، ويتكون تصوره عن العالم: وهكذا يكون أرسطو لا يزال يستبطن ويلبس نمطاً من الفكر الإنساني طوال قرون كاملة، ويكمن في تصوراته الذهنية لا يستطيع الفكاك منها "
  كافٍ جداً ليبين غرضي من قراءة هذا الكتاب.
  
  وفعلاً لم يكن غريباً علي من ناحيتين:
  1- علم الكلام
  2- الفلسفة الإسلامية ومن تأثروا بالمشائية
  
  فالفلسفة الكلامية المتأثرة بالمشائية تأخذ من مصطلحات أرسطو الكثير، بل حتى من بنيته العقلية، وطريقة السبر والتقسيم شاهدتها هنا، وطريق البرهنة من الجزئيات إلى الكليات، من الأسفل إلى الأعلى وجدتها هنا.
  
  قد أكون متعجلة لقراءة هذا الكتاب الآن لأن الاستشكالات لم تأتي لذهني بعد، ولكن لا بأس قراءة أولية لن تضر
  
  الكتاب يتحدث عن العالم الطبيعي، وهذا الكتاب ( الفيزياء ) أحد أقسام الأرغانون الذي جاء بعده ما يتحدث عن الفلسفة الأولى ( الإلهيات بنظرة فلسفية تجريدية ) فسميّت بـ ( ما بعد الطبيعة - الميتافيزيقيا ) بالنسبة لترتيب شرّاح أرسطو وتلاميذه لكتاباته.
  ومنذ ذلك الحين اتخذت الميتافيزيقيا باب أرسطو للولوج من خلاله
  
  الكتاب من ثمان مقالات:
  1- موضوع الطبيعيات ومنهجها
  تحدث عن آراء الأقدمين في المبادئ الطبيعية، والرد عليهم، وانطلق من أن الطبيعة تطلق على ( المادة ) و ( الصورة ) وأن ما تكوّن منهما - أي المادة " الهيولى " والصورة- ليس هو الطبيعة بل أفعال الطبيعة،
  نقاط متفرقة عن المقالة الأولى :
  أن المبادئ إما متحركة أو غير متحركة وأنها متعددة أو واحدة، وأن المتعددة المتحركة إما محدودة أو غير محدودة ؟
  وأن الواحدة اما غير متحركة كما لدى بارميندس أو متحركة عند الطبيعيين كالهواء أو الماء.
  - منطلق البحث عن المطلقات من الأشياء المركبة، هو نتيجة نظرهم للأشياء المتكونة، فهل هي واحدة أم مركبة لتحصيل المبدأ الأول لها هل هو واحد أم كثير.
  
  - أن التكون لابد أن يكون من مبادئ لرفضهم فكرة متخيّلة متوارثة وهي استحالة تكون الشيء من لا شيء، أو خروج الوجود من العدم
  
  - العدم عند أرسطو ليس ( لا شيء ) بل هو ( الخلو من الصورة ) بما أن الوجود عنده هيولى وصورة، فإن العدم هو الهيولى الخالية من الصورة.
  
  2- الطبيعة
  تحدث عن الطبيعة وعلم الطبيعة والعلل الأربعة المشهورة عنه إلا أن الجديد بالنسبة لي هو طريقة استخراجه للعلل الأربعة وهذه أفادتني كثيراً .
  المبادئ عند أرسطو للطبيعة 3:
  1- الصورة
  2- ضد الصورة
  3- الحامل للصورة وهو المادة
  
  - ظريف جداً تفسير أرسطو للصدفة، فالصدفة وما يكون من تلقاء نفسه عنده علل أحدثتها الطبيعة أو العقل بالعرض لا بالذات الأول، والعلة العرضية لا تكون متقدمة على العلة الذاتية.
  
  مثلاً انا رحت السوق باشتري قهوة، لكن في السوق لقيت صديقتي متسلفة مني مبلغ، فأخذت منها ما تدينت مني
  فهنا النظام أني : ر��ت السوق باشتري قهوة
  لكن الصدفة : حصلت المبلغ المُستدان
  فتكون الصدفة هي فعل غائي منظم لكنها لم تكن الغاية بالذات الأساسية التي أردتها
  
  لذلك فالكون بحسب ما فهمت منه نظام ولا تخرقه الشذوذات، وإنما هي تحدث بالعرض، فالصدفة لا يمكن أن تكون بلا علة بل تكون بلا علة غائية بذاتها
  
  أما أساس العلل الأربع المعروفة عنه وهي ( المادية ، الفاعلة، الصورية، الغائية ) فمنشاؤها هو سؤال ( عن الكيف واللماذا ؟ ) ويكون جواب هذا السؤال بين من هذه الحالات :
  1- تحديد الماهية
  2- المحرك الأول
  3- الغاية المقصودة
  4- المادة المكوّن منها.
  
  إلى ان يصل إلى استخراج العلل الأربعة، وفيه فرق بسيط بين العلل الأربع من ناحية الفاعلة والغائية بين الطبيعية والصناعية.
  
  المقالة الثالثة : عن الحركة وتعريفها وهل هي متناهية أو لا متناهية و ... إلخ باختصار الحركة ( هل هي محدودة أم لا )
  
  المقالة الرابعة: المكان ... إلخ كما في الحركة.
  
  الخامسة : تحديدات أولية لدراسة الحركة
  
  السادسة: تركيب المتصل ( وهو ما يتعلق بالحركة والمكان والزمان )
  
  السابعة : البرهان على وجود المحرك الأول : مبدأ العلية
  ثم اثباتات خواصه لدى أرسطو
  
  المقالة الثامنة: أزلية الحركة
  والجدل حول القائلين بها والمعارضين
  
  
  الفصول الأولى هي أساس الكتاب ومن ثم تتفرع المسائل حتى نصل إلى الأخير المحرك الأول
  وجدل أرسطو طويييييييييييييييييييل جداً، ومن ناحية أخرى استشهاده بأقوال الفلاسفة الأوائل ثم الجدل حولها والنقاش.
  
  المتعب في الكتاب أنه يحتاج لنفس طويل للتركيز والمتابعة وهو مبني على مسلمات واهية بالنسبة لنا لكنها بالنسبة له قوية ومؤكدة، مثل:
  1- مركزية الأرض
  2- طبيعة الحركة في الأرض وأنها انتقال للمكان الطبيعي للعناصر لا وجود للجاذبية
  
  
  الكتاب يستحق خمس نجمات لعبقرية المؤلف ولجمال الترجمة.
• 
  J

  Whew, this was one hell of a slough. While it's not strictly speaking a hard book to read, it deals with so many huge, uber-abstract ideas one after the other that it just leaves you exhausted. In some ways it feels more like a Compendium than a strict philosophical text. Aristotle examines every phenomenon that he can think of, Being, Space, Motion, Matter, Time, Infinity, Magnitude, etc. in an attempt to pin down and rationally account for how the universe as he understands it works. It's unrelentingly dense, and obviously quite dated, but at the same time it manages to be pretty enjoyable. It's not so much a straight forward philosophical text as it is a sort of compendium of problems that philosophers have spent the past several millenniums taking a stab at. You might say that it's a work of proto-philosophy, its more concerned with creating a system where these sorts of questions can be fully articulated and worked on than it is in fully solving any of them.
• 
  Genni

  Goodness. Aristotle attempts to cover a lot of ground in 231 pages. He covers opposites, time, infinity, motion, matter, causation, and void with change being the underlying principle experienced by all phenomenon. He attacks atomists and defends teleology. My mind is still reeling, trying to grasp some of his concepts.
  
  “For things to qualify as principles they must not consist of one another or of other things and everything must consist of them”. For Aristotle, change is just such a principle.
  
  His first discussion really hit on something I have been wondering about for awhile, that is the relationship of opposites. My question began in reading Plato's Phaedo where he argues for the immortality of the soul from contraries. I began wondering about applying this argument to love and hate. In Works of Love, Kierkegaard argues briefly that eternal love can never hate, though this seems on the surface to be contrary to certain verses in the Bible. In Categories, Aristotle seems to say that contraries only happen in relations. Here he says that opposites are a scale with some underlying substance constant to both ends, but these are only applicable to physical characteristics? In this discussion, he does not make room for the possibility that say, on a scale from white to black, something may become white from some other color, say red, instead of black. Not sure how this fits, just an observation made by my commentator. In trying to piece together all of this I seem to end up with something like this: Opposites are contrary (in the sense of being in a different position), but not necessarily contradictory. Love and Hate have an underlying strong intense feeling in common, but are not necessarily contradictory? Whereas Loving and Not Loving are the “true” opposites, in the sense of being contradictory.
  
  Anyway, some of his examples of opposites were strange to me. He discusses the coming to being of a house from bricks and vice versa, which to me is a good example of change, but not necessarily opposites.
  
  Physics is also one of the sources of Aristotle's famous “Unmoved Mover” argument. Having heard this referenced a lot, I was super interested to see what he had to say. And I am (perhaps unsurprisingly) confused. He seems to think that the universe is finite, but that time has no beginning or end (unless I am completely misreading him, which is a very distinct possibility). For him, Change and time are inextricably linked and I am having a hard time figuring out how the Unmoved mover, the first and final cause, operates if there is no beginning to time. ??? It is also strange to me that he thinks time is infinite, but that infinity, in a numerical sense is not?
  
  I will definitely have to come back to this one later. I love Aristotle's commonsensical approach to science. It appears to me to be something like an ancient form of empiricism. It's a fascinating, though maybe not entirely comprehensible, look at the physical world.
  
  
  
  
• 
  Ben

  All of the elegance and beauty of modern physics is noticeably missing in the ancient system. The effort made to understand the world is highly impressive in itself even if Aristotle's system did lead to centuries of misconceptions in the field (and still does today considering the widely-used Kalam Cosmological Argument is based of Aristotelian physics), but compared with light bending around stars, black holes ripping matter apart as it crosses the event horizon, or atoms colliding in a particle accelerator, the visual of things going from rest to motion (or from blackness to whiteness) due to an influence from a prime mover is less than inspiring to say the least.
• 
  Briana

  Aaaaaaaaaaaaaaaaaah.
  Aaaaaaaaaaaaaaaaaah.
  Aaaaaaaaaaaaaaaaaah.
  
  This was one of those books that made me think, "I don't understand this book. I don't want to understand this book. I don't need to understand this book. I hate this book. Why am I in college? Why do I read these things? OH LORD NOT ANOTHER 20 PAGES LET ME DIE NOW."
  
  This book taught me how fundamentally immature I really am.
  
  I like my time-space continuum discussion in sci-fi tv shows, not in philosophic definitions.
• 
  Antonette Serine

  Infinity exists only in potential
• 
  Jacob Aitken

  While I am normally hostile to Hellenism, I’ll give Aristotle credit on this point: he was a fairly good communicator. He also set the stage for later scholastic thought (for better or worse). By physics he means things like being, motion, time. Don't think he is talking about the discipline in science today. Like most Greeks, his understanding of science was wrong (to put it mildly). Pascal, among others, refuted him on the nature of the void and vacuum.
  
  We do not know a thing until we know its first principles (184 a10).
  
  Substance is not a predicate. An attribute is that which belongs to the subject (186 b20).
  
  “Being itself.” Substance could mean:
  
  Form
  
  Matter
  
  Complex of both
  
  “The form is indeed the nature rather than the matter” (28).
  
  form: actuality
  
  matter: potentiality (64).
  
  Cause: that out of which a thing comes to be (31).
  
  Formal
  
  Material
  
  Final: first in intention; last in operation.
  
  Book III
  
  Nature--defined as the principle of motion and change. Motion is the fulfilment of what exists potentially (201 a10). It appears he rejects the idea of a transcendent infinite because there is “no such sensible body” (205 b30).
  
  Container notion of space
  
  Dealing with the infinite, Aristotle notes “Nothing is complete which has no end” (207 a14). This rules out Christian theism, for God has no limit yet he is complete and perfect. Aristotle’s discussion on potential infinity, while since surpassed by Cantors, is important for his own time. Further, the infinite, such as it is, is contained (24).
  
  What is a container? The form is that which contains. A place is the boundary between the body and the container (211 b20). This contact creates an organic union “when both become actually one” (213 a9). This is the false view that Thomas Torrance so devastatingly refuted.
  
  Time is a measure of motion and of being moved (221a). Aristotle says that all motion takes place “during a time” (227 b25). Just curious: is there motion in heaven? Heaven’s outside of time. What would it be like to exist in a realm that has neither motion nor time? Contrast that with the Hebrew prophets. I think that is what Aristotle is saying. He notes that “it is impossible for a thing to undergo a finite motion in an infinite time, since time and motion are correlative. In other words, the motion will “max out” the time. Aristotle just rejected the Christian view of heaven, whether biblical or even Platonic (237 b25).
  
  Key argument: everything that is in motion must be moved by something else (242 a17). You can see the later arguments for the existence of God. Something unmoved must already be in place to get the motion going. Book VIII has his famous line of the unmoved mover (260 a19). While I can grant Aristotle’s point that there is an eternal existent, we have no reason to think that it (no need to use personal pronouns) cares for you or would bother to reveal itself by speaking.
• 
  J.C.J. (James) Bergman

  A very interesting book, albeit very dry (but that's to be expected).
  I especially enjoyed Aristotle's views on infinite vs finite universe and first causes, and change.
  I am with Aristotle in a large way insofar as it seems to be a logical contradiction that the universe popped into existence from nothing. Thus, a creator (outside of time and space) seems to be more reasonable. Though, a creator is but one explanation out of many.
  I am not a deist however, since the "deadbeat dad" situation seems unconvincing to me. Why would a creator create us and leave? This seems unreasonable.
  Therefore, I think deism is an intuitively compelling argument for the origins of the universe - but not a satisfactory one overall. This is why I am not committing myself to deism nor theism, but skeptical atheism.
• 
  Havalah Peirce

  Couldn’t make it all the way through this one, try though I might. I blame my personal life for that fact, though—not the book itself, although I admit it was extremely difficult to read more than a few sentences in succession without zoning out. -_-
• 
  Maude Levesque

  From what I understand, Aristotle made this work very difficult and confusing, just so that we would then realize that explaining nature is a very difficult and confusing task and why no one before had been able to precisely do it (it can't be precisely done?) 🥲 ??
  
  Probably important to note that "Physika" means "natural thing"
  
  Aristotle out-aristotled himself and left me more confused than ever
• 
  Yann

  Il n'est pas toujours facile d'intéresser ses semblables à la lecture des auteurs antiques : ils souffrent souvent du préjugés d'être obscures, inutiles et dépassés. Ainsi, la Physique d'Aristote est franchement à déconseiller à qui voudrait les découvrir. Le style est particulièrement lourd, répétitif, et souvent abscons à force d'acribie. Le sujet est la nature, mais Aristote embrasse un périmètre un peu différent que celui que l'on entend de nos jours par "sciences physiques". En effet, pas d'équation, pas de chiffres, pas de chimie, de mécanique ou d'optique. Le principal souci d'Aristote est de résoudre la question du mouvement : pourquoi certaines choses bougent et d'autres non ? Comment se transmet le mouvement ? Pourquoi certaines choses semblent se mouvoir par elles-mêmes ? Quelle est l'origine de ces mouvements ? En posant des principes sur l'essence des choses, et en en tirant des conséquences logiques, Aristote fonde un modèle explicatif de la nature à partir duquel il pose la continuité de la matière et du temps, et élabore une explication originale de l'origine du mouvement, qu'il loge dans une cause première, une divinité dont l'œuvre motrice lui apparait évidemment dans la perfection de la mécanique céleste. Cette œuvre d'Aristote va connaitre une grande fortune au moyen-âge, et sera commenté avec intérêt et passion par des savants juifs, arabes et chrétiens, comme Maïmonide, Averroès ou Thomas d'Aquin, avant d'être rejeté par les modernes comme Descartes, Locke, Newton, qui prennent précisément pour cible l'inutile complexité de ses exposés et la gratuité de ses hypothèses qui ne s'accordent pas avec l'ensemble des phénomènes observables. Il n'en reste pas moins que ce livre est précieux pour connaître les sentiments des Aristotéliciens de l'antiquité, et se faire une idée plus claire des débats théologico-philosophiques qui ont agité le moyen-âge.
• 
  Daniel Wright

  Aristotle's Physics gets a bad rep these days, somewhat unfairly. The book actually is as much philosophy as what we would call science; and though most of the science is mistaken, and some of the philosophy is flawed or contradictory, it nevertheless raises questions that are still not easy to answer. And even when Aristotle is wrong, it's often difficult to see why. I blitzed through this in less than a day, so I can't pretend to have followed all of it by any means.
• 
  Illiterate

  Aristotle is the most impressive of the ancient natural philosophers, but he too relies on speculation and deduction, not experiment and measurement.
• 
  Jesse

  Lots of important stuff here (the four causes, purpose, chance, place, time, infinity, change, ...). His interpretation of intervals as being potentially divisible but not actually made of points seems basically right to me - no need to invent calculus in order to defeat Zeno's paradoxes. It's only after the Cartesian coordinate system & real #s become the dominant model that more sophisticated explanations become necessary, Aristotle's model seems fine too.
  
  The final few sections on change & his deduction of the prime mover were exhausting. He really ties himself into knots trying to explain gravity & momentum in unsuitable terms, and his deductions in these sections were frequently fallacious even for their own time.
• 
  Caleb Abraham

  Horriblement difficile à lire, à l'exception de certains chapitres sur la méthode scientifique, les principes, et les causes. Il conclut la deuxième partie, sur le mouvement, en disant que "le premier moteur meut d'un mouvement éternel pendant un temps infini. Il est donc manifeste que n'ayant aucune grandeur il est indivisible et sans parties" (VIII.X). Ce n'est toutefois pas une notion qui est reprise telle quelle par les chrétiens aristotéliciens, car Aristote parle en réalité de plusieurs moteurs immobiles etc. Ceci dit, l'altération d'Aristote qui s'opère chez les chrétiens est la preuve que la philosophie chrétienne est une philosophie à part entière (contra Bertrand Russel).
• 
  Dorotea

  Bertrand Russell said that you need to study Aristotle's physics even though modern science could hardly accept a single phrase of the book. I agree.
• 
  Vilius Karsokas

  I had difficulties understanding every reasoning displayed by
  Aristotle probably because of the modern scientific outlook of 21st century that had a large influence on me . Nontheless, I was left impressed by capabilities of a man who lived few thousand years ago and on which shoulders future scientific thinkers stood.
• 
  Daniel

  I find Aristotle's Physics as tedious as the next guy, but we mustn't forget what it is we're reading. These are lecture notes on natural philosophy, not "physics" in our modern sense. In this respect, the title is something of a misnomer. Aristotle asks many of the questions that occupy modern-day physicists, such as, what is the essence of nature? what is motion? what causes it? what is space? can space be devoid of matter? what is time? Are space and time infinite or finite? But his procedure for answering these questions couldn't be more different from modern physicists'. There's no math in A.'s Physics. Nor need there be. And that's because this is a work of natural PHILOSOPHY. His approach to the aforementioned questions is qualitative, not quantitative. I'm reluctant to criticize the presentation and style of this text too harshly, considering that these are lecture notes, and poorly translated ones at that. In a sense, I found Aristotle's questions far more interesting than his answers, which were often pedantic and tautological (my translator, R. P. Hardie, may be partially at fault here). Many of A.'s distinctions were also too nice for my taste. I found myself skimming the text, impatient with A.'s byzantine arguments and anticlimactic conclusions. This is not Aristotle's greatest work; the argumentation is riddled with incoherencies, and his method strikes me as too cerebral, too disengaged from the matter and motions he writes about. And that's OK. This was a fascinating intellectual venture, and, for all the needless technicalities, Aristotle managed to come up with some interesting answers to his brilliant questions.
  
  What makes this book a must read, though, is its prominent place in ancient and medieval intellectual history. For all its inaccuracies (Bertrand Russell famously notes that none of Aristotle's speculations about the physical world hold up in light of contemporary science), A.'s Physics was a cornerstone of scientific thought (THE book on natural philosophy) until the Scientific revolution. For 2,000 years, these interesting, if muddled, lecture notes served as the basis for scientific thinking. It's Aristotelian physics, in fact, that Newton, Galileo, and Kepler were rebelling against in the seventeenth century. This, therefore, is an indispensable book in the history of science and of "physics" in particular. So far, the history of physics is a three chapter affair, with Aristotelian physics giving way to Newtonian physics in the 17th c., & Newtonian physics giving way to Quantum physics in the 20th c. (which is still incomplete!).
  
  What is it we're speaking of, though, when we speak of "Aristotelian Physics"? How did Aristotle view the world of objects, movement, space & time? Aristotelian Physics is not elaborated on exclusively in this volume. "De Caelo" is another important text. Here are some of the basic ideas & definitions A. lays out in his Physics:
  
  + Nature is that which has an "impulse to change" (whether this change be coming and going, growing larger or smaller, or altering in any way).
  
  + Aristotle claims that we do not have knowledge of a thing until we have grasped its "why. "Nature is caused by four qualities; it has four "be"-causes, if you like: its formal (i.e., structural), material (i.e., substantial), final (i.e, teleological), and efficient (i.e., immediate) causes.
  
  Take a telephone, for instance. Its material cause is the plastic and metal out of which it is made; its structural cause is the particular shape that it takes; its efficient cause is the industrial production process by which the phone came into being, as well as the laborers who operated the telephone factory machinery; its final cause is its status as a device that will allow two people to communicate across distances. Chance may also be a cause, Aristotle tells us.
  
  + "The fulfillment of what exists potentially ... is motion."
  
  + Aristotle's explorations of time, space, & place are bewildering and inconclusive. He does not develop a complete theory of any of these in his Physics, though he does being to explore them in some detail.
  
  + Aristotle believes in a Prime Mover.
  
  
• 
  Julien Descheneaux

  Je l'ai commencé, je ne le finirais pas. Dépassé, mais reste primordial, selon moi, afin de réellement pénétrer le système aristotélicien.