Do Organisms Exist? 1

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1 AMER. ZOOL., 29: (1989) Do Organisms Exist? 1 MICHAEL RUSE Department of Philosophy and Department of Zoology, University of Guelph, Guelph, Ontario NIG 2W1, Canada SYNOPSIS. What is the status of organisms in modern evolutionary biology? I argue that this is a question which centers on the question of reduction, and towards a complete answer, I pursue issues through three different senses of the term: ontological, methodological, and epistemological. The first sense refers to the ultimate status of the entities of the organic world, and in this sense I argue that organisms have no special status. The second sense refers to the question of organization, and I argue that in the light of modern evolutionary biology organisms do have a distinctive "design-like" organization. The third sense refers to the relationship between theories, in particular to whether the theories of the biological sciences can be shown to be logical consequences of the theories of the physical sciences. I argue that such reduction may be possible in principle but difficult in practice. However, from the perspective of the working scientist, this hardly matters. In conclusion, I argue that in some respects organisms are not distinctive and in other respects they are. Certainly biologists need not worry for the autonomy of their subject. INTRODUCTION Do organisms exist? Obviously in one sense they do. Cows and horses, oak trees and cabbages, slime molds and viruses, and us Homo sapiens. In a way, even asking the question is to get us tangled in Cartesian paradoxes. If we ask if organisms exist, then if we deny there is a positive answer, we thereby assert our own existence; and since we are humans, which are organisms and so on and so forth. But my interest now is not so much in empirical questions and even less in spinning paradoxes. I know that cows and horses exist. I know also that they are different from chairs and tables although I confess that I am not sure how far different are viruses. My question rather is made at the conceptual level. What is it about organisms that makes them organisms? What are the denning criteria for organism-hood? Is being an organism something that we humans make up a subjective construct that exists in our own imaginations? Something we acknowledge because, after all, we have to chop up the world in some way if we are to think about it? But, is being an organism in no sense a reflection of reality? Or is being an organism something that 1 From the Symposium on Is the Organism Necessary? presented at the annual meeting of the American Society of Zoologists, December 1987, at New Orleans, Louisiana we humans discover an objective essence that exists "out there," or at least something that tells us about real divisions in the world of experience? This is a question on the borderline between biology and philosophy it is about the proper subject of a science rather than within the science itself and my suspicion is that many people biologists and philosophers would answer the question rather differently from the way they (at least, inasmuch as one thinks of them as living things) would have answered it (say) two hundred years ago. Certainly differently from how they would have answered it five hundred years ago (Mayr, 1982). Then, they would have answered unhesitatingly that organisms did exist, they did have an essence which separates them from non-organic entities, and, however this may be picked out by individual people or cultures, the defining mark of an organism is the possession of vital force it is this unseen but real power that separates the living from the nonliving. Now thanks to the ongoing successes of the physical sciences, people are nothing like so sure. The biochemists have shown us that organisms are made of the same material things as everything else remember when you were told that your body consisted of a few pints of water, a handful of chemicals, and two or three thumb tacks, in total value about $5?! And the molecular biologists have shown that the very fabric of life is made of the same

2 1062 MICHAEL RUSE particles as the rest of the universe. Perhaps talking of "organisms" is, after all, no more than an anthropomorphic conceit of our ignorant human nature. If I have correctly represented the dominant way of thought today and I think I have, especially of those scientists who have most successfully brought the physical sciences to biology then I have to confess to a feeling of personal unease. I doubt that one can ever give a truly definitive answer on these matters. After all, these are questions which have been discussed at least from the time of Aristotle, that is, about two and a half thousand years. And I certainly have no wish to go back to vital forces (for reasons which I shall explain in a moment). But I do want to suggest that organisms are more than just molecules, or inorganic substances. We may be a gallon of water and a handful of chemicals, but we are more than just that. In some sense, organisms do exist. They are different. How does one set about putting some flesh on intuitions mine or those who might take issue with me? The problem is surely basically one of reduction: Can the living world be reduced, in some important way, to the non-living world? Or, is it forever different? And this being the matter at issue, there are valuable discussions on which we can draw to aid our inquiry. Specifically, here I will rely on a three-part division by the biologist Francisco Ayala (1974), between (as he calls them) ontological reductionism, methodological reductionism, and theoretical reductionism. I take them in turn. (In choosing Ayala, as you will soon learn, in no way do I intend to belittle the importance of the work of others, especially such seminal thinkers as Ernest Nagel, 1961.) ONTOLOGICAL REDUCTIONISM The ontological reductionist claims that material objects ultimately the microobjects of physics are all that there is. Nothing else exists. At once, this simple statement would seem to go against powerful world-pictures, particularly those of the religious. How can one reduce God to molecules? However, it seems fair to say that today, at least, ontological reductionism does not have theology in its sights. Nor, conversely, should the Believer fear such reductionism (Peacocke, 1986). On the one hand, ontological reductionism is usually construed as a thesis about science. God's status lies outside any such construal. On the other hand (pertinent to our inquiry here), no one would want to claim that God is an organism anyway. The real target of the ontological reductionist is the already-mentioned believer in life-forces: the "vitalist." Now, let me say at once that if one is to dismiss vitalism, one must not at least, one should not simply put it down with a sneer, as oldfashioned. After all, life does seem different from non-life. Proper counter-arguments must be given. Nor can such arguments be simply that one does not see vital forces, that they are invisible or otherwise beyond detection by the human senses. I have never seen a molecule, yet I do not doubt that they exist. Neither do I doubt that your mind exists, even though were I to split open your head I would not see it. The proper argument against vitalism and this I think is as decisive as these arguments can ever get is that the invocation of vital forces does absolutely nothing to further our understanding of the organic world (Hempel, 1966). Unlike molecules (or minds for that matter) they lead to no new predictions or controls or explanations or unification. Put the matter this way. Take two organisms, identical except that one is powered by a vital force and the other is not. There is absolutely no reason today to think that the one would work whereas the other would not, or that we would be able to say anything interesting about the one other than that it had a vital force that we would not be able to say about the other. Vital forces may not be contradictory, but they are redundant, and that is about as bad. I have said that ontological reductionism asserts that only the micro-entities of physics exist. What about minds? Do these not take us beyond material objects? It must be admitted that some think they do socalled "dualists" like Descartes and (in our own times) Sir Karl Popper (Eccles and

3 Do ORGANISMS EXIST? 1063 Popper, 1977). At this point, it seems to me that you must choose between options. You must deny dualism, perhaps asserting some version of the identity thesis, where mind and brain are seen as different sides of the same thing. Or you must deny ontological reductionism, and admit that some organisms at least go beyond the purely material. Or what comes to the same thing you must extend the meaning of ontological reductionism to cover thinking substances as well as material substance. I myself, like I suspect most Anglo-Saxon philosophers today, tend towards some version of the identity thesis (Churchland, 1984). But I shall not argue this case here, which could indeed not be done without very considerably extending this discussion. What I shall say is that whether or not minds are made of some ultimate worldstuff, while they are undoubtedly confined to organisms, 1 see no reason to restrict them purely to humans and many reasons not so to do. If we apply to organisms the criteria we apply to humans, and if we take into account our shared evolutionary heritage, then while a cauliflower almost certainly does not, have a mind, a chimpanzee almost certainly does. It may not be as advanced as ours, but it is there. Descartes denied that non-human animals have minds, but the modern-day dualist has no more right to assert this than does the strictest adherent to ontological reductionism. (Have I not been too quick in discussing vital forces, if I am prepared to allow minds whether as distinct substances or as manifestations of matter? If minds exist, in some sense, why not vital forces? My answer is first that we surely have a direct awareness of minds that we do not have of vital forces whether minds are within the realm of science, they do rather press themselves upon us. Second, by Hempel's pragmatic criterion, I am not convinced that minds are as useless as vital forces. Take two organisms, identical except that one has a mind and the other does not. Would they be as well adapted? Take two computers, identical in hardware and software, except that one has an operator who understands the programme and the other does not. Do they function equally well?) METHODOLOGICAL REDUCTIONISM The methodological reductionist claims that the bigger can always be understood in terms of the smaller and usually adds that this is the best kind of understanding. Paradigmatic examples include the explanation of the behaviour of gases in terms of very small particles, and of the behaviour of light in terms of micro-waves. To set the scene, let me note that although the opposition is by no means confined to one group exclusively, these days the most vociferous critics of methodological reductionism tend to be the Marxists. Following especially Engels, they argue that new levels emerge as one goes up in size and complexity, and that these in principle cannot be understood in terms of lower levels (Levins and Lewontin, 1985). I confess that in discussions of methodological reductionism I often sense some fairly commonsensical claims dressed up to look like metaphysical (or mystical) profundities. At least, I often sense claims being made with an air of awe (or aggressiveness) that surely no one would really want to deny (Nagel, 1961). In particular, what cannot be denied and hence cannot be denied by the methodological reductionist is that the more entities you have, the more the whole question of organization becomes important. Take a straight line, say 5 cm long. It is a straight line and that is that. Now take three straight lines, 3 cm, 4 cm, and 5 cm. Put them end to end, and you have a straight line of 12 cm. Connect them, and you have a right angled triangle, of which all sorts of new properties like Pythagoras' theorem hold. Clearly, something new has emerged something which could not be understood or explained from the constituent parts, taken separately. But, who would ever doubt this? The only problem for the methodological reductionist would come were one to argue that taking organization into account necessarily precludes an explanation of the larger in terms of the smaller or, at least, makes such an explanation less than ideal. This, however, is an entirely different kettle of fish for which (to the best of my knowledge) argument is quite missing.

4 1064 MICHAEL RUSE Leaving aside the question of whether explanation should strive to be in terms of larger resting on smaller the smaller the better and recognizing that, whatever else may be the case, we certainly can practice methodological reductionism in biology in fact this is the way that most biologists work most of the time the question for us, given our interest in the nature of the organism, is whether there is something distinctive or peculiar about biological organization. Is there that something about the nature of organisms which makes them different from non-organisms? 2 Many have certainly thought so, and not to conceal my hand-^tam inclined to agree (Ruse, 1973). It is felt that the key mark of the organic lies in its being enddirected or forward-looking or teleological. In organisms, parts are understood in terms of the ends that they serve, and not merely in terms of the causes that brought them about. To quote Ayala: "Teleological explanations account for the existence of a certain feature in a system by demonstrating the feature's contribution to a specific property or state of the system" (Dobzhansky et al., 1977, p. 498 [his italics]). You ask, what is the function of the hand or the eye, or what purpose does the bark of the tree serve. You do not ask about the function of the canals on Mars, or the purpose of the tides (Beckner, 1969). The nineteenth-century, pre-darwinian philosopher of science William Whewell put the point well: In living things the parts make up the whole, but the existence of the whole is essential to the preservation of the parts. But parts existing under such conditions are organs, and the whole is organized. This is the fundamental conception of organization. "Organized beings," says the physiologist, "are composed of a number of essential and mutually dependent parts." "An organized product of nature," says the great metaphysician (Kant) "is that in which all the parts are mutually ends and means."... The system is organized when the effects which take place among the parts are essential to our conception of the whole; when the whole would not be a whole, nor the parts, except these effects were produced; when the effects not only happen in fact, but are included in the idea of the object; when they are not only seen, but foreseen; not only expected, but intended: in short when, instead of being causes and effects, they are ends and means, as they are termed in the above definition. Thus we necessarily include, in our Idea of Organization, the notion of an End, a Purpose, a Design; or, to use another phrase which has been peculiarly appropriated in this case, a Final Cause. This idea of a Final Cause is an essential condition in order to the pursuing our researches respecting organized bodies. (Whewell, 1840, Vol. 2, pp. 620) Of course, the reason why Whewell argued as he did was because he thought that God had miraculously created organisms (Ruse, 1979). Now we are evolutionists, and most of us give Darwin's notion of natural selection a crucial role. However, the forward-looking teleological understanding remains. Only half in jest, the well-known evolutionist Richard Dawkins (1983) speaks of himself as out- Paleying Paley. It is true that Dawkins is an ardent Darwinian and not all are as keen on natural selection as he. It is true also that no one has argued at least, not since Cuvier that every last aspect of organisms is teleological (Gould and Lewontin, 1979). Apart from anything else, there are homologies to be accepted and accounted for. But the end-directed organization of organisms produced by natural selection so that they may survive and reproduce is a distinctive facet of the living. Rocks simply don't work!! This question bears strong affinities to the question of the existence and reality of species. I provide a discussion of that topic, in a way paralleling this discussion, in Ruse (1987). THEORETICAL REDUCTION Third and finally, I come to the kind of reduction which requires that you show that

5 Do ORGANISMS EXIST? 1065 one set of scientific claims are logical consequences of another set. This can (in principle) occur within a science intratheoretic reduction or across a science intertheoretic reduction. Much has been written on the topic by philosophers, and as one who has been much involved in controversy. I am hardly that disinterested. But were I to make broad claims, the following would seem particularly germane to our discussion here. First, there seems to be nothing about organisms which makes theoretical reduction even the explaining of organism by the principles of physics logically impossible. The dramatic way in which such reduction might be prevented would occur if organisms actually violated the principles of physics. But this never occurs. Creationists claim that organisms violate the second law of thermodynamics, but this is no more true than that a cloud violates gravity. The second law states that entropy always increases but it applies to closed systems, whereas organisms taking in food and excreting waste are open systems. Not that this is to deny that a remarkable aspect of organisms is the way that they keep one step ahead of the maw of the second law. That, for a while (until they die) in their own limited domain, organisms reverse the entropy flow is part of a pervasive characteristic of the living, namely the way that it is "goal directed" (or "directly organized") towards survival and reproduction. If things start to run down, or if disruptive influences intrude, organisms can (with all the obvious qualifications) right themselves and get back on track. The same applies to individual parts (not necessarily all parts). If a human gets overheated, for instance, it starts to sweat to bring the temperature down. If it gets too cold, it starts to shiver to bring the temperature up. Let me simply say here that although goal directedness is a marvelous aspect of organic nature, it is not a miraculous one (Nagel, 1961). Using models based on machines for seeking moving or changing ends, like torpedoes, much light has been thrown by biologists and philosophers on the nature and working of goal directedness. Suffice it to say that there has been no need to invoke extra-scientific factors. The second point I would make about theoretical reduction is that it does seem now that physico-chemical laws are moving in to offer explanations of organic phenomena phenomena which were previously explained either by biological laws or not at all (Rosenberg, 1985). One thinks, for instance, of the ways in which our understanding of the DNA molecule throws light on heredity, particularly on areas previously covered by Mendel's laws. And one thinks also of the work on life's origins, using the idea of hypercycles and centering on the key function of the RN A molecule, by Manfred Eigen and his associates (1981). However, whether these powerful molecular explanations actually reduce, in the sense of "rigorously imply," the biological explanations, or simply replace them entirely, is a matter of debate. And also it must be noted even if the tightest kind of theoretical reduction is occurring (or, at least, made possible), the physico-chemical explanations must take account of biological organization. But, of course, they do this. The whole point about the DNA molecule, for instance, is that it takes on its meaning according to the order of the sub-molecules in the chain. Shuffled one way, you have (the possibility of) a mouse. Shuffled another way, you have (the possibility of) an elephant (Grene, 1987). My third, and final point is that, even if theoretical reduction is possible, this is not to deny that organisms might show certain "emergent properties" not found at the level of the molecules. (I am thinking now of properties which go beyond mere organization, as the colour green might be said to emerge from the mixing of blue and yellow.) However, this kind of emergence always happens in theoretical reduction, and demands the invocation of "dictionaries" or "correspondence" or "translation" rules, to go from the concepts of the reducing theory to the concepts of the reduced theory (Schaffner, 1967). In the theory of gases, for instance, you need a principle allowing you to identify mean kinetic energy of the gas particles with temperature of the gas. When it comes to

6 1066 MICHAEL RUSE understanding organisms, even at the molecular level, I am not sure that there occurs any particularly new dimension beyond this conceptual point. You will need the appropriate dictionary, but if (say) you identify some particular muscle with some particular molecular configuration, the principle seems no different from the identification of energy with temperature. That something is living does not alter the logic of theoretical reduction. THE QUESTION ANSWERED Do organisms exist? Well, yes (and this is not a reluctant "yes") and, no (and this is not a reluctant "no"). If you are asking if organisms have some special essence or substance, then the answer is "no." (Qualify this by noting that if you are a dualist, then you do think that some organisms have a special substance in mind. But possession of this is not a defining feature because there are organisms without minds.) On the other hand, if you are asking if there are special features or properties distinguishing organisms, then my answer is "yes." Organisms are teleological or enddirected. There is that about organic organization which is different. I do not know if there are borderline cases. Perhaps there are (viruses?). As an evolutionist, I am not at all worried by the fact that the real world does not divide as neatly as the world of Euclidean geometry. In conclusion, let me stress that as a Darwinian, I do not find the teleology of organisms mysterious. It is a direct result of the force that shapes the whole of the organic world: natural selection. Yet, at the same time, I shall have failed in my discussion if I do not leave you with a sense of respect for evolution's results. Organisms may not be mysterious. There is plenty of room left for wonder. REFERENCES Ayala, F Introduction. In F. Ayala and Th. Dobzhansky (eds.), Studies in the philosophy of biology. University of California Press, Berkeley. Beckner, M Function and teleology. J. Hist. Biol. 2: Churchland, P. M Matter and consciousness. MIT Press, Cambridge, Mass. Dawkins, R Universal Darwinism. In D. S. Bendall (ed.), Evolution from molecules to men, pp Cambridge University Press, Cambridge. Dobzhansky, Th., F. J. Ayala, G. C. Stebbins, andj. W. Valentine Evolution. W. H. Freeman, San Francisco. Eccles, J. C. and K. R. Popper The self and its brain. Springer-Verlag, New York. Eigen, M., W. Gardiner, P. Schuster, and R. Winkler- Oswatitsch The origin of genetic information. Sci. Am. 244(4): Gould, S.J. and R. C. Lewontin Thespandrels of San Marco and the panglossian paradigm: A critique of the adaptationist programme. Proc. Roy. Soc. Volume B 205: Grene, M Hierarchies in biology. Am. Sci. 75: Hempel, C Philosophy of natural science. Prentice-Hall, Englewood Cliffs. Levins, R. and R. Lewontin The dialectical biologist. Harvard University Press, Cambridge, Mass. Mayr, E The growth of biological thought: Diversity, evolution, and inheritance. Harvard University Press, Cambridge, Mass. Nagel, E The structure of science. Routledge & Kegan Paul, London. Peacocke, A God and the new biology. Dent, London. Rosenberg, A The structure of biological science. Cambridge University Press, Cambridge. Ruse, M The philosophy of biology. Hutchinson, London. Ruse, M The Darwinian revolution: Science red in tooth and claw. University of Chicago Press, Chicago. Ruse, M Species: Individuals, natural kinds or what? Brit. J. Phil. Sci. 38: Schaffher, K. F Approaches to reduction. Phil. Sci. 34: Whewell, W Philosophy of the inductive sciences. Parker, London.