Mortimer Adler lectures; The continuity of nature, part 1

How does man differ from everything else on earth. The University of Chicago presents the 1966 Britannica lecture series. The difference of man and the difference it makes. Our guest speaker for this series of five lectures about the position of man in the natural world is Mortimer J Edgar director of the Institute for philosophical research. This first lecture is titled The continuity of nature. First of all let me remind you of the single question with which these lectures are concerned. How does man differ from everything else on earth. To this question there are three answers which emerge from two distinctions. The first distinction is that between difference in degree and difference in kind. Two things different in degree when. With respect to some common attribute a characteristic one has more of it and the other less and between two things differing in degree intermediates are always possible

two things different in combine. When one possesses natural beauty or characteristic totally lack by the other the law of excluded middle applicable to differ to differences in kind but not to differences in degree here rules out intermediates. The second distinction is that between two ways in which things can differ in kind either superficially are radically. That's we have three possible answers to the question of how man differs from everything else. They are in degree only I see three possible answers in degree only. In kind as well as in degree but only superficially in kind. In kind as well as in degree but in some if not all respects radically in common. Of these three possible answers to the question the first and second in degree only or most of officially and con those those two are compatible with the continuity

of nature only the third a radical difference in Con makes man discontinuous with the rest of nature. Not in all respects of course but in whatever respect or respects he differs radically in conduct from the Greeks to the 18th century. The question of how man differs was treated as if it were a purely philosophical question a question that could be satisfactorily answered without investigation by philosophical analysis in the light of common experience. It is only in the last hundred fifty years at most and mainly in the last hundred years that scientific investigations and theories based on scientific data have contributed to the solution of the problem. In the present lecture and the lectures to fall out we are going to consider the question in its proper light as a mixed question to its scientific evidence and theorizing are critically relevant. But before we embark on this effort it will be useful to summarize briefly the state of

the issue as constituted by a purely philosophical approach to the question. Remembering that that purely philosophical approach to the question is definitely inadequate. Suppose I ask you to suppose that no scientific evidence no scientific evidence had ever been brought to bear on the answering of this question. Suppose that we had nothing but the arguments of opposed philosophical theories about the order of nature. And the difference of man. Where would we be now. Which side of the issue would we should we favor with the issue be resolved. Would it be resolvable in commenting on the state of the issue considered as if it were a purely philosophical issue. I will do so first with respect to the order of nature and second with respect to the difference of man. Philosophical analysis clarified our understanding of continuity in relation to

kinds. It called attention to a basic error made by certain philosophers who tried to conceive the order of nature as a continuum of kinds or species. Not only did Locke and lipids commit this area but they also tried to combine their assertion of a single all embracing continuum with the contradictory assertion that nature consists in a hierarchy of radically distinct kinds inert bodies plants brute animals man at the apex. If a single all embracing continuum in nature is incompatible with the can hierarchy of kinds and if a continuum cannot be a continuum of condoms but must consist solely of a very very Asians in degree. What then are the philosophically tenable alternatives. Aware of the contradictions that I've just pointed out the manual can't

answer this question in the following manner. On the one hand he regarded the tendency to find continuity in nature as one of the regulator principles of reason in man's effort to understand and know the world. This tendency led the mind to find sameness in things and to allow only for differences in degree. On the other hand he regarded the tendency to distinguish things as different in kind as also a regulator principle of reason governing man's effort to know and understand the order of nature. This tendency led the mind to find otherness in things and introduce this continuities of nature for the mind to operate in accordance with either one of these regulated principles to the exclusion of the other. What in Kant's view result in falsification and the erection of a half truth as if it were a whole into the whole truth. But Kant also held that to apply both principles

without limitation results in contradiction. For the order of nature cannot be both a single all embracing continuum and a set or hierarchy of distinct kinds. Kant thought we was saved from this antenna me. Only by the fact that we could not empirically support either principle applied without limit to the exclusion of the other. We must and for MUST In short according to Kant look for continuity in nature on the one hand and we must try to discover distinct kinds on the other. But we must not suppose that either of these regulative principles can be converted into the one and only objective truth about nature. While I think that Kant's insight into the problem is in part correct I do not think that his statement of the entity is correct nor that we are obliged to accept his resolution of it. I would express what is correct about hands inside in the following manner. No

universe real or possible is intelligible unless it contains some sameness and some differences. For any two things which exist or any two objects of phone it must be true that they are the same in one or more respects and that they differ. In one or more respects. They cannot be utterly the same. And they too. They cannot be utterly different and be existences or thinkable those for three existences are alike in that respect. If they are thinkable they are alike in that respect. But it is quite possible for two things to be completely the same enchain and yet still to death. If they differ only in degree the degree to which they possess the same characteristics is also possible. A point not notice by Kant for two things to differ superficially enchain while still being exactly alike in their underlying makeup of constitution.

Hence a single all embracing continuum in nature need not exclude all differences in allows for differences in degree and for superficial differences in kind. It excludes only it only excludes radical differences in kind. For of such exist there must be an underlying discontinuity in nature. On the other hand the principle of hierarchy excludes a single all and bracing continuum but it does allow for a paralysis of continuum of separate continua that permit a lower kind to approach the next higher kind. By a scale of degrees. I can now summarize my answer to the question that I asked a little while ago. What are the philosophically tenable alternatives. They are to. One the one hand the principle of continuity understood as allowing for difference in degree and for superficial differences in kind. But excluding radical differences in kind. That's one

alternative. The other ends of the possible to a tenable tenable when possible. The principle of hierarchy understood as asserting radical differences in kind and allowing for a plurality of partial continua within the sphere of each of the distinct kinds. But to deny. The existence of a single all embracing continuum of nature these two principles of these two answers that I just given are contradictory. Both cannot be true. Where the analysis that I'm offering you differs most fundamentally from tat is in the surging back of the two alternatives. One can be true and the other can be false. And since I think that basic continuity and basic discontinuity in nature are not only exclusive but exhaustive. I would go further assert that one of these two principles must be true and the other false. This philosophical clarification of the issue about the order of nature

controls our treatment of the question about the difference of man. Not only is a purely philosophical question but also is a mixed question. The introduction of scientific evidence bearing on the question does not and cannot all of the picture so far as the relevant relevant principles are concerned precisely because they are principles and a determination of how man differs whether in the light of common experience alone or in the light of all the scientific evidence now available or that ever will be available must be in accord with one of the other of the two opposed principles the principle of continuity or the principle of hierarchy. So much for the philosophical issue about the order of nature. Now what about the question concerning man's difference treated still as or were a purely philosophical question here at first blush it would seem at first blush it would seem as if the position that asserts man's radical difference in kind had the edge of the argument over the position of the classical materialists

who asserted that man diff is only in degree for two reasons first because the common experience of mankind falsified is that the award tends to falsify the view that man differs only in degree from other things or the view that throughout the whole of nature their only difference is of degree in material complexity. Second because the doctrine of animistic or mechanistic materialism quite apart from questions about the order of nature and about the difference of man is falsified by a common experience to accept the doctrine. We must to reject our common experience as Il is already. If our common experience is not healers already we must reject the doctrine. The Dialectical materialism of the marxists is able to affirm manifest differences in kind and also to maintain the principle of continuity in nature. It is able to do this by positing critical threshold in an underlying continuum of degrees. These explain the manifest differences in kind

and in so doing render them superficial rather than radical dialectical materialism asserting the basic continuity of nature is therefore not falsified by common experience for the allows for the reality of differences in kind. But the cause of the difference is in kind that we find in our common experience. In addition both dialectical materialism and also mechanistic materialism as that now has become in our century much more sophisticated and subtle regard themselves as able to maintain their doctrine without treating common experience as it was already in any respect. These things being so the affirmative position the position that says that man differs radically in kind loses the advantage you appears to have at first blush. The issue and I can't I can't overemphasize the importance of the point and I'm going to make the issue treated as if it were a purely philosophical issue appears to be irresolvable neither side can persuade the other. By philosophical

arguments alone if it were it would remain as a philosophical issue would go and be debated from Natalie end of time and undecided. On result on the on the on the one hand scientific evidence is needed to establish as a matter of fact the critical threshold is posited by the dialectical materialists without which observed differences in kind cannot be reconciled with the underlying continuity of nature. On the other hand even if the if the the position which asserts that man radically differs in kind has additional philosophical arguments to offer in support of that proposition I think these arguments I think cannot settle the matter without submitting themselves to empirical tests not just by reference to common experience but also by reference to the special data obtained by scientific investigations. Hence we see both the necessity and the advantage of dealing with the question about man's difference in its proper light as a mixed question

involving both science and philosophy. And the question is rended mixed by the introduction of two different bodies of scientific investigation theory one earlier than the other though both now concurrent in this century the first and somewhat earlier entrance of science into the picture is represented by the obvious relevance of the theory of evolution in general. And by the facts of paleoanthropology in particular the second and somewhat later entrance of science is represented by the behavioral sciences in general especially in the area of comparative studies of human and animal behavior and also by clinical and experimental researches neurology. In this lecture I will deal with the relevance of the facts and theories of evolutionary biology. Next I will deal with the evidences and theories of the behavioral sciences. Tonight I will proceed as follows. I would like first to give you a brief summary of the thinking about

continuity in species in the century before Darwin. Both in general and as applied to man because there are some things that are said. Said then that a very significant Second I'd like to state for you the bearing of the theory and the facts of evolution on the problem of continuity of species in Darwin's day and in post Darwinian biology down to the present day. Third I would like to state the position taken by Darwin and his contemporaries on the question about man in the light of evolutionary fact in theory. And finally going from Darwin to the present day by talking about the relevance of paleoanthropology physics the significance of the fossil remains the fossil discoveries all all or almost all except the two. Since Darwin's day. Let me try it once. To think the thinking that was done about continuity in species in the century immediately before God while they were not scientific

investigators investigators in the full sense of that term as being called an investigator is applicable to Darwin and his contemporaries. The eighteenth century writers were naturalists who took account of evidences that lie outside the common experience of mankind to the extent that they did. They constitute a transition from the purely philosophical to the next treatment of the question about man's difference. They also represent. And this is important. The adoption of the extreme view the extreme view at the principle of continuity in nature allows only for differences in degree with the consequence that species are nonexistent and that distinctions enchain are killers are or at best only apparent. Not really. I will deal first with the theory of evolution. I want to watch this separate step it. I want to talk first about the theory of evolution quite apart from man forget as if that man didn't exist. I act as if you simply had all the other living organisms other than man.

Beginning with Darwin and coming down out of the present day in the theory of evolution without regard to man. And then after that having done that I will deal with the question about man in the context of evolutionary theory and research has handled first by doubt without the benefit of Paley in paleoanthropology anthropological research and evidence and is treated and then is treated in our day in the light of all the fossil remains we discover. I turned it once to the problem of continuity in species in the light of evolutionary research. Here is a brief exposition of Darwin's theory of evolution and speciate speciation. The theory of biologic biological evolution as formulated by Darwin can be summarized by say that it can vary its likeness is principle of continuity into a temporal law law developed all over the various forms of life including forms now extinct and forms now extinct are connected

developmentally in the succession of countless generations in each of which the offspring vary slightly from their ancestors and from each other. Differences multiply. But at the point in time and space and which they first occur. They are slight. Almost insensible differences in degree borrowing borrowing the expression which like this like this first gave currency to Darwin repeatedly declares now Tura known fact that salt. Nature does nothing by jumps. If fire jump. Is meant the crossing of a gap that is made by a real difference in kind of a difference constituted by one things having a characteristic totally liked by the other. Then the expression the maximum Nature does nothing by jumps means that evolutionary development by descent with modification from ancestral forms excludes the reality of kinds to this extent. Down would appear to be the agreement with those of his immediate predecessors

who espouse the principle of continuity in its most extreme form. And if Darwin had done only that he might have a theory of evolution. I temporized developmental version of the principle of continuity in nature. But he would not have had a theory of speciation and a theory of the our region of species varieties or races of one of the same species like individual members of a species may differ from one another only in degree. But if the diverse species of a single genus are to be distinguished from the diverse varieties of a single species the difference between species must be one of kind. Darwin expresses many doubts about the possibility of distinguishing varieties or races from species. He often says back in the hours he says over and over again that species are really nothing but

well marked varieties. There is no problem here. Of course if the naturalists taxonomic scheme is something that he imposes upon nature for his own convenience. If the kinds or groupings that he sets up are artificial. But if his class distinctions are supposed to represent natural kinds natural groupings a different kind not just in degree then he's a confronted. With the problem of reconciling natural kinds with his evolutionary principle of developmental of phylogenetic continuity. For if evolution is a continuous development of living forms from living forms without jumps by and sensible gradations are differences in degree. How is it possible for new species to come into being at any point in the developmental continuum. Or to put the question in a somewhat different way. Must not the taxonomist this classification of living organisms of a living organism

now extend into a large number of distinct species. The artificial something imposed on nature rather than the representation of divisions actually existing in nature itself. It would look as if Darwin's answer to this question should have been in the cold with the one given by Robert Lee. That species had no reality for if he had given that answer. But but if he had given that answer if he had given an answer he couldn't develop the theory of the argument species. The answer it gives agrees with Robin way and conforms to the principle of continuity in one respect it denies that the difference between species is a real difference in kind. It denies that species are kinds between which intermediates are impossible to it which mean it's a possible rather But another respect. His answer departs from Rabelais even though species are not really different kind of species are nevertheless According to Darwin. Naturally existing

groups that appear in a different kind they cause the intermediates that might have connected them by a continuous series of gradations in degree are absent or missing the absent intermediates often call the missing links in the chain create the appearance of a difference in kind between species. Between the varieties or races of the single species there are no missing links are absent in the medians. The metaphor missing links is unfortunate because the chain does not convey the image of a continuous series. I prefer to speak of gaps or breaks in the continuum like the interference bands or eruptions in the spectrum of light that is. Before you. And apparent difference in kind exists where any medians though possible are absent where intermediate stop possible are absent and so a gap or break occurs in the continuum of

degree. Let me illustrate this. The chromatic spectrum the rainbow is thought to be a continuous series of commanding qualities and one moreover that is carried with a continuous series of degrees of wavelength. When bands are blackouts I introduced into the spectrum the colors separated by the bands opinion different kind. This continuously. But we know that the only apparent because we know that the discontinuity can be removed by removing the bands of blackouts and thus reinstating the continuum of kinetic qualities. In contrast to that a real difference in kind exists where intermediates are impossible and where Therefore there is a discontinuity as opposed to a merely broken or interrupted continuity. The lack of a broken or redirected continuity can be repair at least in principle by restoring the absent in the media is the real discontinuity. Can it be turned into a continue. By

treating species as naturally existing groups or organs of organisms that are only apparently different in time separated Islanders in an interrupted continuum. Darwin developed a theory of speciation that did not violate his evolutionary principle of developmental continuity. Species originate species originate according to his theory by a process of natural selection that operates to perpetuate certain varieties and to cause the extinction of other riders. Thus giving rise to gaps or interruptions in the Continuum without which there would be no species. If anyone ever asks you what Darwin What is the cause of the argument species the answer is the extinction of immediate arrivals. That's the operating principle that in natural selection anything else but the answer to that question is the extinction. For if the enemy varieties were none extinct there would be no gaps or interruptions in the Continuum and there'd be no species.

Viewed it developmentally This means that the organisms we distinguish at a given time as different species of the same genus were represented at an early time at an earlier time by ancestors that were distinguished as races a variety of the same species that. At the earlier time there were also intermediate races a variety. But through the process of natural selection these gradually became extinct so that with the extinction of these it immediately arises the extreme varieties tended to separate genetically through various barriers to interbreeding and thus they became distinct species of a single genus where earlier their ancestors were merely different varieties of the same species. That's the whole story in a nutshell. View taxonomically deal taxonomically not developmentally This means that at a given time co-exist and species are distinct kinds only by virtue

of the absence of intermediate forms of varieties that become extinct and that if the geological record. Regular fossil forms were complete instead of imperfect and if fossil remains unable to reconstruct all previously existing organisms we could repair the broken or interrupted continuum by filling in the gaps and we could just re-establish it one time. The continuity of nature with no difference isn't kind not even apparent. But only differences in degree. That's Darwin's picture. Let me now try to briefly briefly summarize the import of Darwin's theory before turning to the Poste Darwinian modifications in the theory of evolution and his speciation. Darwin's theory of developmental continuity excludes the possibility of there being any radical difference in kind among the species of living things. For if there were it would be impossible for them to be connected in the phylogenetic series constituted by slight variations in

degree. Nor could they have originated nor could they have originated by the extinction of innovative varieties through the operation of natural selection. Now they are two species does not mention man except in a single sentence in the concluding pages where Darwin says quote I quote light will be from on the origin of man and his history in later editions he changed this to much like will be thrown. In the same concluding pages however. Darwin does consider the question whether they Arjen of life is monophyletic or powerful. That means from one and said Strong is a more type offer a plurality of ancestral organisms or type.