The evolutionary contingency thesis
Sandra Mitchell believes ECT demonstrates the natural necessity view of lawfulness should be abandoned in favor of a pragmatic view. Each account offers important lessons about the role of biological laws. However, each response has important problems. Rather than accept one view to the exclusion of others, I argue that the proper response to ECT is a synthesis of important features found in each account. I use this synthesis to sketch a virtue based account of science: disciplines that employ sufficiently virtuous tools and practices are viewed as scientific, even if a discipline is lawless.
My discussion has three components. Second, I discuss the advantages offered by each response to ECT and concerns that prevent us from accepting any particular response. Finally, I outline a synthesized account of virtue based science. Login Lost password? Create account.
Natural selection rewards past events, that is, the production of successful recombination of genes, but it does not plan for the future. This is, precisely, what gives evolution by natural selection its flexibility. With the environment changing incessantly, natural selection-in contradistinction to orthogenesis-never commits itself to a future goal. Natural selection is never goal oriented. It is misleading and quite inadmissible to designate such broadly generalized concepts as survival or reproductive success as definite and specified goals.
I suspect that there is a misunderstanding here of what Ayala had in mind. The latter emphasizes that he does not mean that natural selection tends towards the production of specific kinds of organisms or that evolution as a whole proceeds towards preconceived goals. Natural selection does not "plan for the future," but it is not just a way of explaining the past either, as Mayr suggests.
Il portale dell'evoluzione
It is also future-oriented, but because of the multiple contingencies of the larger evolutionary process of which natural selection is the only non-random aspect, it cannot guarantee that future. Maintaining that natural selection has a goal does not imply that the goal will always be achieved. Natural selection is predictive only in a quite limited sense: given a suitable environment, a hereditable genetic variation favoring reproductive fitness will gradually spread in a population.
Where Ayala is perhaps incautious is in holding that the evolutionary process itself and not just natural selection can be regarded as teleological in character, in the sense of being directed to the improvement of "the reproductive fitness of a population in the environments in which it lives," as well as having the "potentiality of producing end-directed DNA codes of information.
It is sufficient to hold that one causal component of the overall evolutionary process, natural selection, is goal-directed; it is this that gives evolution its often directional-seeming appearance. But the overall process is so beset by contingency that the use of the term 'teleological' in its regard is almost inevitably going to lead to misunderstanding.
What are the implications of the revival of teleological language in biology for the issue from which we began? It does validate the use of the language of purpose in specific biological contexts relating to the economy of the organism as a whole or in part, where functional explanation would also apply: "the purpose function of the protein, cytochrome C, is to aid in cell respiration.
Is natural selection goal-directed? Ayala and Mayr disagree, as we have seen, and their disagreement would be mirrored in the biological community generally. It is one thing to say that the liver has a purpose, a function; 43 it is not so obvious that one can say the same thing of natural selection. But because natural selection is only one aspect of a process fraught with contingency, it seems strained to use the language of purpose in its regard. Evolutionary explanation is retrospective, agent-causal, concerned to establish origins. Even though the features of the living world that it explains are, many of them, teleological in character, the explanation it offers is itself in no real sense teleological, does not invoke a purpose.
Even less does it involve design. From Plato to Aquinas to the natural theology of the seventeenth century, 'design' connoted evidence for conscious purpose, for an active Intelligence responsible for the origins of the feature in question. To see something as embodying "design" was to allow inference to a Designer as the only possible genetic cause. This is why I regard it as misleading for some writers on evolution to speak of "design without a designer," to recognize two possible sources of design: "one in the intentions of agents and one in the action of natural selection.
Richard Dawkins' book, The Blind Watchmaker, offers a striking example of the confusion that this looser use of the term can lead to. On the one hand, the sub-title of the book reads: "Why the evidence of evolution reveals a universe without design," and the argument of the book itself is said to show how natural selection can give "the illusion of design.
To summarize, then, the term 'design' is to be avoided in describing either the teleological aspects of organisms or the work of natural selection.
Philosophy of Macroevolution (Stanford Encyclopedia of Philosophy)
They are not to be used of the overall evolutionary process from the scientific standpoint. Does this, then, answer the question from which this essay began: given the contingency of the evolutionary process as a whole, and specifically of the process that led to the appearance of human beings on this planet, can one meaningfully speak of the outcome of these latter processes as being the product of purpose?
Not in the scientific sense, evidently. That is, the evolutionary explanation of human origins does not require the postulation of an active Platonic shaping purpose at work or even of an immanent Aristotelian goal-directedness. Indeed, if anything, it seems rather to rule both of these out. If purpose is to be attributed to the evolutionary sequence leading to the human, support for it will have to come from a different quarter.
Adaptation is real, and it is achieved by a progressive and directed process. The process is wholly natural in its operation. This natural process achieves the aspect of purpose without the intervention of a purposer; and it has produced a vast plan without the concurrent action of a planner. It may be that the initiation of the process and the physical laws under which it functions had a purpose and that this mechanistic way of achieving a plan is the instrument of a Planner-of this still deeper problem the scientist, as scientist, cannot speak.
Though natural selection is a "directive" and "creative" "pseudo-purposive" factor back of adaptation, it is "not always the decisive factor in evolution and it never acts alone. How is that to be understood? Simpson does not say. Gould, in passing, has a suggestion to offer. He is, as we have seen, more insistent than anyone else on the fragility of the evolutionary line leading to the human. But he recalls a tentative solution that Darwin once offered to the difficulty that weighed so heavily with him in his later life: how could a good God permit the suffering that is everywhere evident in the living world?
Perhaps, Darwin suggested, one might say that, while the details of the operation of nature are a matter of chance, God is responsible for the laws that underlie this operation. The admittedly rather half-hearted suggestion on the part of both authors is, then, that there may be enough lawlikeness, despite the prevalence of contingency in individual evolutionary lines, to sustain some sort of claim for cosmic purpose.
Aristotelian or Platonic? That is, is it the immanent "purpose" of a goal-directed behavior at the cosmic level or is it the conscious "purpose" of a shaping Agent?
They leave it open. What about the former? It would require something analogous to a "good" at the cosmic level; a lawlike process like the cosmic expansion of itself would not be sufficient.
The speculative Gaia hypothesis-that the earth tends to maintain itself in a sort of homeostatic equilibrium-would be a teleological explanation of that sort, the "good" here being the preservation of the Earth's "balance," however the latter might itself be defined. It is difficult to envision an analogue of this sort of "good" at the level of the universe of expanding galaxies. Might it be longevity? But an "Aristotelian" teleology itself, as we have seen, leads one to ask for a "Platonic" agent-causal explanation: how and why did this goal-directedness come to be?
So this brings us back to the second sort of purpose, the conscious purpose of a creative Agent. And in this context we still face the challenge that the radical contingency of the evolutionary process poses to the achievement of conscious purpose. This is not, it should be noted, a matter of discerning purpose in the evolutionary sequence and inferring from this to a Purposer. That would resemble the traditional Design argument, and we have already seen that, from the standpoint of the synthetic theory of evolution, evidence of design, of the work of conscious purpose, is not to be found in evolutionary process.
Rather, what we are asking here is the more oblique question: might not this process, despite its contingency, still be consonant with the achievement of purpose on the part of a creative Agent? Surely their appearance, then, must be more than a cosmic accident from the standpoint of the Creator? It is true that some Christian theologians have been developing the relatively non-traditional view that God's efficacy is limited in regard to the achievement of ends within the created order.
Vanstone bases his argument on the nature of loving relationship:. The activity of God in creation must be precarious. It must proceed by no assured programme. Its progress, like every progress of love, must be an angular progress-in which each step is a precarious step into the unknown If the creation is the work of love, then its shape cannot be predetermined by the Creator, nor its triumph foreknown.
Keith Ward offers a nuanced argument, drawn in part from metaphysics, in part from Biblical theology. A contingent universe can only be accounted for if one makes free creativity a characteristic of the First Mover, which entails placing change and contingency within the First Mover itself. John Polkinghorne agrees with Ward in holding that God is temporal.
But he maintains that limitations on God's knowledge and power are freely chosen on God's part, a kenosis, or emptying, freely undergone, akin to the kenosis that Christians already find in the doctrine of the Incarnation: "God has permitted a kenosis of his omniscience, parallel to the kenosis of his omnipotence. Even he does not know the unformed future, and that is no imperfection in the divine nature, for that future is not yet there to be known. The vulnerability that these authors, and others who hold similar views, speak of bears to a large extent on God's relationship with creatures who can exercise free choice.
They do not ask whether the existence of such creatures was in the first place defeasible. Ward remarks that God causally determines "those outcomes which are necessary to the fulfillment of the dynamic purpose. But how does God causally determine the outcome of evolution? This brings us right back to the question from which we began.
Those who maintain that God's purposes are limited by God's own nature or the nature of God's relationship with the world might still be persuaded to allow that the advent of human beings was something God knew from the beginning would happen.