Teleological Explanations in Biology

Biologists tend to use teleological language in explaining the origin and evolution of living organisms and their characteristics. As John Reiss has pointed out (Reis, J. Not by Design: Retiring Darwin's Watchmaker, University of California Press, 2009), this entails the idea that evolution is necessarily a teleological process. This entails the idea that evolution is not a "natural" process, like gravity or oxidation, and that therefore there is some "non-natural" component (i.e. "magic") in biology that fundamentally distinguishes it from the other natural sciences.

Evolutionary biologists like Richard Dawkins try to make this distinction when referring to the problem of human free will (see "Let's all stop beating Basil's car"), but unless they are careful about how they talk about evolution (especially natural selection) they revert to the same teleological descriptions and explanations that Reiss so decries. What is the problem, here?

I believe that the underlying problem is the tendency by most evolutionary biologists to think of natural selection as a "force" or "mechanism". As John Endler has pointed out (Endler, J. Natural Selection in the Wild, Princeton University Press, 1986), natural selection is not a "force" or "mechanism", it is an outcome. To be precise, it is the outcome of four separate, but related processes:

• Variety: structural and functional differences between individuals in populations,

• Heredity : the inheritance of structures and functions from parents to offspring (either genetically or epigenetically),

• Fecundity : the ability to reproduce, especially (but not necessarily) at a rate that exceeds replacement, and

• Demography : some individuals survive and reproduce more often than others.

As a result of these four processes, the heritable characteristics of some individuals become more common in populations over time.

Notice that the same list of processes can be used to explain non-adaptive evolutionary change (e.g. genetic drift). Also notice that the only source of new phenotypic variations is what I have called the "engines of variation": all of those processes that produce heritable phenotypic changes in phylogenetic lines of organisms in populations. There are at least fifty such processes (you can see a summary list here). While it is the case that "random mutation" is included in this list, there are many other processes in this list that do not involve "mutation" (in the genetic sense) and which also are not "random" (at least insofar as that term is often used).

Is there a real distinction between non-teleological and teleological processes, or are all processes either teleological or not? If all processes (i.e. changes over time) are teleological, as asserted by Aristotle (and some of the commentators), then there is no point in talking about it. However, if some processes are teleological and some are not (as most people, including presumably most of the commentators here, now believe), then the question becomes "how can one distinguish between teleological and non-teleological processes, and what explains the differences between them?"

In his comprehensive analysis of teleology, Andrew Woodfield (Woodfield, A. Teleology, Cambridge University Press, 1976) pointed out that all teleological descriptions can be reformulated to conform to the linguistic formula " x happens in order to/for y outcome." He also asserted that such linguistic formulations describe metaphysically real processes. That is, some processes are genuinely teleological – they involve pre-existing designs or plans that cause processes to tend toward particular outcomes, regardless of perturbations or outside interference – while other processes only seem teleological – they involve laws of nature, such as gravity, that result in particular outcomes, without responding actively to perturbations or outside interference.

This distinction is essential when considering whether "genuine" teleology exists. To be precise, teleological descriptions sound "reasonable" when they are applied to genuinely teleological processes, but sound ridiculous if they are applied to non-teleological processes. For example, does it sound reasonable to say that when you drop a rock, it falls "in order to" reach the ground? By contrast, does it sound reasonable to say that birds have wings "in order to" fly? Is there a difference between the "reasonableness" of the first teleological explanation and the second?

When I pose this question to my students, almost all of them say yes: the first is ridiculous and the second isn't. I then point out that this implies that the origin of the wings of birds therefore seems to be the result of a teleological process. I then point out (reprising Aristotle) that there are at least four ways of explaining the presence of wings:
• "this bird has wings because it is composed of materials that are assembled and operated as wings" (Aristotle's "material" cause);
• "this bird has wings because its parents had wings" (Aristotle's "efficient" cause);
• "this bird has wings because birds have wings" (Aristotle's "formal" cause); and
• "this bird has wings in order to fly" (Aristotle's "final" cause).

Since at least the 17th century (and mostly because of Newton), natural scientists have stopped using formal or final causes to explain natural phenomena...except in biology. This was first pointed out by Colin Pittendrigh (Pittendrigh, C. S. Behavior and Evolution) (ed. by A. Rose and G. G. Simpson), Yale University Press, 1958), who coined the term "teleonomy" to refer to the kind of teleological phenomena observed in biological processes. Francisco Ayala modified and extended Pittendrigh's analysis (Ayala, F. J. 'Teleological Explanations in Evolutionary Biology', Philosophy of Science, vol. 37 pp. 1-15, 1970). Ernst Mayr finally sorted the whole thing out in 1974 in "Teleological and teleonomic: A new analysis" (Boston Studies in the Philosophy of Science, vol. XIV, pp. 91 -117). According to Mayr, the difference between the "behavior" of dropped rocks and genuinely purposeful processes is the presence or operation of a pre-existing information-containing program in the latter. Rocks do not fall because there is an encoded program in nature that makes them fall. They fall because there is a force (i.e. a law of nature) that causes them to fall. However, a bird has wings because there is a program encoded within its genome which, as the result of interactions between the "phenome" of the bird and its environment, causes the construction and operation of wings.

To say that natural selection is teleological would therefore require that there be a pre-existing encoded program somewhere that would cause natural selection to bring about its effects. This is ridiculous for at least two reasons:
• there is no such program as far as we can tell (where would it be encoded?), and
• this would require that natural selection be a process in and of itself, rather than the outcome of the four processes listed above.

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As always, comments, criticisms, and suggestions are warmly welcomed!

--Allen

Why Intelligent Design Supporters Insist That ID Must Be True

It has taken me a very long while, but I think I finally understand why Intelligent Design (ID) exists, why websites like Uncommon Descent exist, and why the regular commentators who support ID at those websites are so determined to assert the absolute reality of ID, in spite of a complete lack of empirical evidence.

It’s all right here in this quote about the ultimate justification for morality:

“Of course [the validity of an objective moral code] is all dependent upon the truth of the existence of God and the truthfulness of scripture - most of us here are aware of that.”

I believe that this is the crux of the whole science versus ID debate: if there is no empirical evidence for the existence of God, then it all comes down entirely to pure, unsupported supposition. Yes, one can assert that God exists, and can assert that therefore whatever God asserts must, by definition, be the absolute objective truth, but by the standards of scientific logic (which are now almost universally accepted as providing the most reliable evidence for descriptions of reality), arguments based purely and solely on assertion are no longer considered valid.

Ergo, without some independent source of evidence – independent of the original assertion, that is – then it all comes down to dueling assertions, which means that eventually it all comes down to force majeure: whoever can make the most forceful assertion gets to define the Truth.

Therefore, there must be some kind of empirical evidence for the existence of God. The fact that no one has ever found any is completely irrelevant, and will remain so indefinitely. It also explains why it is perfectly legitimate to deliberately distort, misinterpret, omit, or otherwise alter empirical evidence if it does not support the otherwise unsupportable assertion that God exists. [1]

Here is the way it looks to me:

Condition #1:

• If a moral code is not objective, it is ipso facto invalid.

• The moral code asserted by God is the only objective moral code. [2]

• If God does not exist, then there is no basis for the assertion that there is an objective moral code.

• Therefore, if God does not exist, anything is permitted.

Condition #2:

• An argument supported purely by assertion(s) is invalid. [3]

• Ever since Francis Bacon’s Novum Organum, it has generally been considered necessary that there should be empirical evidence (either direct or indirect) in support of arguments.

• Ergo, there must be empirical evidence in support of the assertion that God exists. Otherwise, there can be no objective morals, and therefore anything is permitted.

Conclusion:

Since God must exist (otherwise there are no morals and anything is permitted), then there must be empirical evidence for His existence. Finding none, it is therefore necessary to pretend that some exists, or to make some up. Otherwise there can be no objective basis for morals, society will necessarily collapse into chaos, and we will all inevitably become insatiable, maniacal, cannibalistic, orgiastic mass murderers, rapists, and thieves.

It also seems to me that this is the reason why ethical philosophers now virtually unanimously agree that ethical prescriptions cannot be derived from statements derived from empirical science (i.e. "ought" cannot be derived from "is"). To do so not only conflates two separate domains of logic (i.e. deductive versus inductive), but also requires that there be empirical evidence for something (i.e. ethical prescriptions) that are not and cannot be justified by empirical analysis (i.e. the workings of nature). Yes, we can use empirical analysis to determine if our ethical prescriptions have brought about the goals which we have decided to pursue, but we cannot use empirical analysis to formulate those goals.

Notes:

[1] Unsupportable on the basis of empirical evidence, that is.

[2] An obvious corollary to this is that each and every one of God’s moral prescriptions is both objective and absolutely True, by definition. Hence the argument that anything God prescribes (such as the massacre of the Canaanites) is morally right, simply by virtue of His saying so.

[3] To be specific, arguments based purely on deductive (i.e. Aristotelian) logic have been largely superseded by arguments based on inductive logic.

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As always, comments, criticisms, and suggestions are warmly welcomed!

--Allen

The Resurrection of Formal and Final Causes

SOURCE: Telic Thoughts

COMMENTARY: Allen MacNeill

Over at Telic Thoughts, g arago commented:

"It would perhaps help to bring in Aristotle's causes again, to the effect that final causes are virtually eliminated from modern science. Postmodernity enables the case for formal causality to re-emerge as a legitimate source of (scientific or non-scientific) knowledge."

It's interesting that this should be proposed, as that is precisely what I will be doing during the very first meeting of my "purpose in nature" seminar at Cornell this summer. It is a sad fact that most undergraduates (and an alarming number of philosophers and scientists) do not know anything about Aristotle's doctrine of causes, nor how they relate to the work they are doing.

Aristotle identified four causes for every phenomenon:

Material Cause: What the object in question is composed of (e.g. a house is composed of boards, bricks, mortar, etc.;

Formal Cause: What formal category the object is an exemplar of (e.g. any particular house is a "house" or dwelling place for people);

Efficient Cause: What immediate processes bring about the existence of the object (e.g. the carpenters, etc. are the efficient cause of the house); and

Final Cause: The purpose of the object (e.g. carpenters et al build houses "in order to" provide dwelling places for people).

In modern science, both formal and final causes are considered to be unnecessary, and are therefore not generally included in scientific explanations of natural objects and processes. However, it is not strictly true that formal causes have been completely eliminated from science. Much of physics, for example, has taken on some of the characteristics of "formal cause" insofar as physical processes are describable and predictable using formal mathematics. This is particularly the case for physicists who believe that actual physical phenomena are "the working out of underlying mathematical relationships."

The same could be said for evolutionary theory insofar as the "modern evolutionary synthesis" initiated R. A. Fisher, J.B.S. Haldane, and Sewall Wright sought to lay a formal mathematical foundation for biological evolution.

The problem for "intelligent design theory" therefore is to show (if possible) that final causes are necessary (i.e. not just psychologically gratifying or theologically convenient) for evolutionary explanations of natural objects and processes. Final causes (or "purposes") are not entirely missing from evolutionary biology, as shown by the work of Colin Pittendrigh, Francisco Ayala, and Ernst Mayr, all of whom debated the appropriateness of teleological language when referring to adapations. However, no evolutionary biologist has resorted to teleological explanations for the existence or operation of natural selection, speciation, evolutionary development, or other central processes in evolution, at least not recently. The reason for such exclusion has not been an antipathy to theologically based explanations per se, but rather the simple fact that teleological explanations for evolutionary processes have been shown repeatedly to be unnecessary, and therefore irrelevant (notice that I did not say "untrue," as "truth" is also irrelevant in this context).

What W. Dembski and M. Behe and other ID theorists have attempted to do (in my opinion, so far unsuccessfully) is to re-integrate teleology into evolutionary processes. The more recent discussion by some ID theorists of "'front-loaded' intelligent design" is simply a reinvention of Aristotelian formal cause, and as such is indistinguishable from classical deism. Neither of these approaches to "design or purpose in nature" has yet been successful as scientific enterprises because they have not been shown to be indispensible to scientific explanations. Until they are, they will not be integrated into mainstream science. While I personally do not believe they can be, I am willing to be shown otherwise by people who use direct empirical evidence and strong inference to show how teleological explanations are necessary for scientific explanations.

--Allen