"metaphysics and modern science" A bit of history. Aristotle and ta meta ta phusika. Descartes and the begining of modern philosophy. Kant and the "Metaphysical foundations of natural science" Positivism General Concepts of Metaphysics Most general features Anecdote Second order generalities Examples - state, space, time, event, property, thing, change, matter Why Science? Tradition mind, god, freedom, etc. Criticism Positivists answered Testability and two science informed metaphysics case studies Thanks for coming everyone. Even though this presentation is on contemporary metaphysics broadly construed, I thought I'd start with a bit of history, to get everyone up to speed, so as to get a grip on the historical dimension of the discipline; I also do this to make my presentation a bit more of a "something for everyone" kind of deal. So, let us put on our historian hats for a few minutes and journey back to visit good ol' Aristotle. One of his works is the first work of metaphysics labeled as such. But it is important to realize that Aristotle himself did not name this work; Aristotle's works are often lecture notes and this one has come down to us with the name a librarian gave to it. "Ta meta ta phusika" basically means "after the works on nature" in the sense of later on the shelf. Ironically, I am going to suggest in due course to actually invert this, and suggest that we view metaphysics as in some sense prior to the study of nature and society, in other words prior to our sciences of all kinds. Aristotle's work is very intricate, and deals extensively with many things still dealt with to this day in metaphysics: cause, for example. But it also deals with things such as contradiction which we today associate with logic. So metaphysics is both very old and has changed over the years. Aristotle does share with me the general view that metaphysics should ally itself with science, though; indeed, the reason for having ta meta ta phusika at all is because the two integrate quite well. So let us skip forward approximately 2000 years, and look briefly at another great metaphysician and his work. At the begining of the modern period, Descartes pondered the general features of reality like his predecessor, Aristotle. He called the discipline "first philosophy", and so do I, suggesting that it is first on the list of philosophical disciplines. Of course, I also have a zeroth philosophy, but that's another story for another time. Descartes' metaphysics, like that of Aristotle, was intimately tied into his philosophy of religion and theology. I mention this because to this day another meaning of metaphysics is something like "religion" or "faith" and when I discuss the linkage between metaphysics and science I do not mean this at all. In due course we shall see why this is so, but for now, let's look a bit more about the features of both Descartes and Aristotle's metaphysics. Both were speculative in the sense that they did not deal much with experimentation or empirical evidence. Contemporary metaphysics is like this too, and for this reason, the positivists disliked it. But before we get to them, we must stop at Kant and look at his metaphysics. This is not the time to survey the monumental and dense Critique of Pure Reason, but instead, I'd like to talk about Kant's "Metaphysical foundations of natural science". Commentators, critics, etc. of Kant have thought for a while that Kant was a philosopher of the new mechanics, that Kantianism is an outgrowth of Newton's work in some respect. I applaud Kant, because that's exactly what he appears to be trying to do in this work. Unfortunately for him and the commentators who want to show Kant's remarkable prescience get it wrong here. In this work, Kant tries to work out a more generalized version of Newtonian mechanics and gravitation. Unfortunately, Kant misunderstood these, and so the generalization produced involves a universal repulsive force introduced to balance out the attractive force of gravity. I mention this not to bash Kant or his commentators, but to note how badly wrong they got it here. No universal repulsive force is needed in Newtonian mechanics, and confusion over this is still present in some contemporary debates about causality. I shall return to this in due course; suffice is to say large numbers of philosophers are still *Aristotlian* when it comes to causation. Kant was one of them, in a weird sort of way. (Those of you who have studied the first critique may know that Kant thinks causality is not in things themselves, this is true, he does, but that's irrelevant to the present purpose.) I also point this out because one criticism of metaphysics that is recurrent is its testability. Well, there we have an example of a metaphysics in the sense I use it that can and has been tested and found wanting. (The sad thing is that Kant's scheme was stillborn - it was refuted before its creation.) I want to point out that Kant had the right idea, as did Descartes (to a lesser degree) and Aristotle, that metaphysics was connected with science. So then we come to positivism. Auguste Comte is often credited with being the first positivist; I understand that he named it. (Arguably Francis Bacon was actually, but that's another story.) Comte thought that development of society and accounts of the world went through three stages, religious, metaphysical, and positive. He thought that the scientific revolution of the 17th century was primarily metaphysical, replacing religious concepts with those that go beyond appearance. The positive stage was to replace these with concepts having to do with experience. In that sense metaphysics was necessary, but being overcome. Comte's 20th century successors, the so called logical positivists analyzed meaning and the like in a way somewhat reminsent of what Comte considered positive. Important for our purposes is that both made contact with science, albeit in a strange way. Comte praised Fourier's heat diffusion equation because it postulated no mechanism. Today we call that an example of a phenomenalistic hypothesis. The logical posivists went one step further, denouncing the metaphysical - in this case, what goes beyond experience - as meaningless. But if metaphysics is the study of the general features of reality, as we saw Aristotle, Descartes, and Kant thought, the posivists did have a metaphysics - a phenomeanlistic one. I shall mention this again in the context of general metaphysics. So? Where are we now? We've got a mixed history. Let's salvage what I think is worth salvaging. Let's look at some traditional metaphysics concepts and see that they are still used in science in general. This is modelling metaphysics after what the geneticist Richard Lewontin said is one of the aims of science. He said that science looks for (and presupposes, for that matter) generalities in the world. I suggest that because some concepts are general to all science, we should look at these concepts as being metaphysical in nature. Low and behold, there is a strong overlap between these and the notions of conventional metaphysics. So the accusation that I am simply playing a word game (I have been accused of this when giving similar lectures and discussions on other occasions) is false. What are these concepts? State, space, change, time, event, cause, property, matter, and so on. All of these are found in sciences from physics to history. There are of course other traditionally metaphysical concepts found only in a few sciences: mind, will, and a few related ones, for instance. These are only found in biology, psychology and the other mixed and social sciences. I guess it is fair to say that these are still metaphysical. But what of some concepts? "God" is one of them. Is there room for a concept of god in science oriented metaphysics? That's not an easy question. Descartes and Aristotle thought they had metaphysical arguments for why god was a legitimate part of metaphysics. I think all of these fail and further there is no other reason (a la Kant, for instance) to suppose that there is any need for such a concept. Be that as it may, much contemporary metaphysics in the philosophical sense - not in the venacular sense - is atheistic as well, so I am hardly alone. In any case, the point is simply that having a science oriented metaphysics does not entail that all traditionally metaphysical concepts are found in science. But what are the roles of these concepts? The positivists thought they were dispensible in some way; why am I claiming they are not? Well, that's a matter of investigation. I move that we cannot do science without these concepts. Since opening a monograph or textbook on science will show that these concepts are widely used, I dare say the burden of proof is on those who would dismiss this evidence. Needless to say, this applies case by case. But what of the other argument, that metaphysics goes beyond the senses and is thus wrongheaded for that reason. Well, first of all, it is important to realize that this isn't always true. Berkeley, for instance had a phenomenalistic metaphysics. The positivists had a similar one; the basic features of the world were sensations and so on; I understand that the young Carnap took this (to me strange) view very seriously. In fact, science needs to go beyond the senses in order to work. Remember I said that Fourier was praised by Comte. Well, suppose we wanted to learn more than just the diffusion equation? I take it as given that this is desirable. We want to know *why*. We do this by postulating entities and processes beyond the senses. The ancient atomists did this; it is a tradition that is still with us. Of course, the positivists are not quite consistent on this point. They will no doubt recognize the indispensibility of these hypotheses, but will probably tell us a story about their fictional status, their being part of a "linguistic framework" or the like. Well, this is not quite fair for two reasons. One is what is often called an inference to the best explanation. Now, unless you really take seriously the notion that "esse est percipere vel percipi", the world does behave as if there were these things called atoms, for instance. So why not extend that to the metaphysical notions I mentioned previously? Second, we can *test* these hypotheses even though they do go beyond the senses. This extends to metaphysical ones. Let's take Aristotle's famous "everything that moves is moved by another". Now this is subtly ambiguous as stated, but recall that Aristotle meant it as meaning that at least unalive things (except for the prime mover) had no ability or power to move on their own. Debate over this is still considered by some philosophers when free will and the like are debated. I move that this worry (if it is one) can be falsified by physics. Let's look at why. Here of necessity my presentation becomes a bit technical, but hey, no science or profound philosophy without tears, as Russell said. Consider Newton's second law of motion, written in modern differential notation. This is F = m d^2x/dt^2, where x is position, t time, m mass, and F force. Forces are causes in Newtonian mechanics, so asking whether Aristotle was right about them amounts to asking whether the aforementioned differential equation has nontrivial solutions when F = 0. For those of you who have the mathematical background, you can check me when I assert without doing the integration that the equation does have nontrivial solutions when F = 0. For those of you who don't, I suggest that this is a reason to ally science with metaphysics - without science one might be still speculating on this, as many philosophers still are. My own work is on events, and they too have to be reworked and understood a little differently in the light of physics as well. But this is not a big deal; in fact, it overcomes one of the weaknesses of metaphysics pointed out by the positivists (and by Kant, to some extent, too) - namely that it is not easily refutable and changable. But there we have it, we've refuted a general thesis about causation, a very metaphysical concept. Sometimes the metaphysical questions asked are very obscure indeed. Kant wondered about absolute versus relative space. Some of you may know his famous "hand" problem. Well, this is a bit more visual and less mathematical than an investigation into causality and involves some pretty pictures, so let's end by looking at this problem. Kant wondered what would happen if the universe consisted of a single hand. He claimed that since this hand would nevertheless be a right hand or a left hand, it had to stand in relation to something (rather than another relation) in order to be such. He famously thought this was to space itself. How the argument goes is relatively obscure. However, we can update his argument in light of physical chemistry. [pass sheet] Are the two molecules on the sheet of the same kind? What does it depend on? [get an answer] [continue as appropriate] This is made the more clear in these models I have here. You will notice that they are *not* of the same molecule. I challenge anyone to turn one one into the other without removing any representation of bonds. Those are the grey things. You will notice that one model is a mirror image of the other. In that sense at least the molecules are handed. Chemists call this chirality - which is when something is not superimposable on its mirror image. I have thus transferred Kant's "hand problem" into the domain of chemistry. How does this help? Well, it turns out that molecules like these rotate the plane of plane polarized light. One of them (I don't know which) rotates it to the right a certain amount, and the other to the left the same amount. In that sense one is "right handed" and one "left handed". Now what? Well, it turns out that one can do a long and rather intricate calculation on many molecules and determine which handedness they are merely by their structural features. Kant was wrong, at least when it comes to molecules! I should note that this process is generally too involved; a chemist wanting to tell these apart has a naming convention that distinguishes the two regardless of their actual effects on plane polarized light. One will be labeled "R" and one "S", but that is independant of the direction of rotation of plane polarized light. Stereochemistry has helped us in philosophy! Who would have thought it! Oh, yes, I don't claim that we have exactly solved Kant's problem, but we have shown it is not a matter necessarily to be settled by pure reason. Thanks.