Philosophy of Religion III
Phil1000-02 10/06 Lecture Fall, 2006
The Teleological Argument
The teleological argument (i.e., „argument from design‟) is usually taken as an argument from analogy, which is a kind of inductive argument.
P1) The world is like a watch in its complexity and purposiveness. P2) Watches are designed by intelligent beings. C) Therefore, so was the world.
Note that complexity by itself isn't enough to make the argument good: complexity must be for a purpose. We have to be careful that we don't read purpose into something just because it proves useful to us. Normally, we have to find an organism's own purpose (not the purpose it was intended to have for its maker).
This is one problem with the watch example: Paley almost has to treat the watch as if it's an organism. We have a much harder time finding a genuine purpose for inorganic systems; even Aristotle had his doubts here.
However, this is not a crippling problem. For suppose we were to find irreducible genuine purpose in part of nature; we might well suppose that the rest of nature is designed to support that purpose.
It‟s a favorite argument of the 18th Century. It is also Biblical:
The heavens proclaim (exemplify) the glory of God; the invisible things of God are clear from the visible things of this earth.
Since the argument is inductive, it provides at best a good, but not a conclusive, reason for accepting its conclusion. More recently, some philosophers have suggested that the argument is better seen as a different kind of non-deductive argument: an inference to the best explanation (which is an abductive argument). The form of such an argument is roughly something like this:
P1) Suppose you accept a set of data D. P2) Suppose you need to choose between two theories H1 and H2, both of which are compatible with D. P3) Given H1, D is only to be expected (is probable). P4) Given H2, D is a surprise (is not probable). C1) Therefore, H1 is a better explanation than H2 of D. C2) Therefore, H1 should be chosen. In short, we should prefer the theory under which the observed data are more likely than under any of the theory‟s competitors.
The argument from design is then roughly taken this way: P1) The data are complex natural phenomena that are apparently goal-directed but not products of human design. P2) The competing theories are: the phenomena are products of intelligent design; the phenomena are products of natural forces (unguided by intelligence). P3) The phenomena we observe can only be expected if they are designed; they would be surprising if the products of merely random natural forces. C) Therefore, we should prefer the explanation that they are designed by an intelligent being God.
Taking the argument from design as abductive explains certain things. First it explains why Hume, in criticizing the argument, considers alternative theories (such as the notion that the universe is a giant animal, or a giant vegetable, or that teleology is just built into it).
He accepts the claim that the hypothesis of design is a better explanation than the hypothesis of creation by natural forces; and unless he comes up with a better hypothesis, this will commit him to accepting the argument from design. His failure to find a better hypothesis (remember that he lived 100 years before Darwin) explains his partial capitulation in the last part of the Dialogues.
Second, and more importantly, it explains why the argument has seemed weaker and gained less acceptance since 1859, the year of publication of The Origin of Species.
The hypothesis that intricate, seemingly goal-directed natural phenomena are the products of natural forces gained credence. Those natural forces now are generally taken to include genetic mutation, consequent heritable variations, natural selection, and resultant speciation.
As a result, given the natural forces hypothesis, the existence of natural phenomena is indeed probable. Hence, abduction no longer gives reason to prefer the design hypothesis over the natural forces hypothesis. This means that if the latter is better supported for other reasons than the former, it looks bad for the design hypothesis.
The natural forces hypothesis is committed only to what Gould calls the fact of evolution -- i.e., to the claim that natural forces have brought about the production over time of all present species from a common ancestral stock.
This is a very generic claim, since it‟s not committed to any version of “evolutionary theory”, but what is important is that it‟s supported by such (undeniable) data as common DNA coding in extremely diverse species, for that is precisely what the natural force hypothesis predicts.
Accordingly, it appears that there is actually an abductive argument against design here:
if species were separately created, common coding would be an unexpected (surprising) result.
Further, the design hypothesis makes certain phenomena more surprising (less probable) than proponents of that hypothesis have supposed.
Certain structures in nature appear to be far from ideal design solutions: e.g., the human knee, the panda‟s thumb. Evolutionary theory suggests that what comes about is an adaptation of pre-existing structures, and thus can rarely be expected to represent an ideal design solution.
Thus, given evolutionary theory, less than ideal structures are to be expected; whereas, given design theory, on which organisms are designed independently and from scratch, such structures are a surprise. Thus we should conclude not only that the design hypothesis is not better than the natural forces hypothesis, but that the natural forces hypothesis is better than the design hypothesis.
Note that the argument from design, qua an abductive argument, takes design and evolution as competing hypotheses. Not everyone regards them as such.
Many have noted that the notion of purpose is often of heuristic value in biological sciences, and take this as evidence that the natural forces hypothesis presupposes design.
But it‟s important to recognize that to treat biological entities as if they were designed is not to accept the design hypothesis, any more than to treat a teenage criminal as an adult is to believe he is actually an adult.
orthogenesis
One alternative is orthogenesis, which tries to combine both design and natural forces.
it is the hypothesis that life has an innate tendency to move in a unilinear fashion due to some internal or external "driving force“.
This has large problems: e.g., wastefulness, seeming randomness of species extinctions, etc. At the very minimum, evolution by natural selection does not give a reason for accepting orthogenesis. So anyone who accepts evolution has no solid reason for agreeing to the hypothesis of purposive intelligent design, as a matter of how things are (regardless of its heuristic value).
Nonetheless
Paley, Hume, and other 18th-Century thinkers were not wrong in seeing an important element of analogy in the argument.
The reason why design a plausible explanation for complex, apparently goal-directed, natural phenomena is because they are like what we already know to be products of design: namely, humanly manufactured objects.
Thus the abductive argument from design works, if at all, because the design hypothesis is supported by an analogy.
Structure of AA
P1) A has features w, x, y, and z. P2) B has features w, x, and y. C) Therefore, B (probably) has feature z.
A is the Primary Analogate and B is the Secondary Analogate of the analogy. w, x, and y are Common Features and z is the Inferred Feature of the analogy.
Take special note of two necessities in any argument from analogy: First, the trait in dispute must be relevant to the common traits cited, or the argument is no good. The argument from design easily passes this test: purposive complexity is causally relevant to design.
Second, the presence of disanalogies weaken (and the absence of disanalogies strengthen) the conclusion‟s likelihood.
However, any points of disanalogy cited must be relevant to the trait in dispute, or the attempted disanalogy is irrelevant, and thus unproblematic.
Thus, it‟s not an objection to point out that all watchmakers have or had appendices and are under nine feet tall.
Objections
In dealing with any analogy, it's always open to a person to refuse to accept any particular point suggested by the analogy.
E.g., the analogy suggests that God has hands, but a believer need not accept that.
But every point not accepted is then a point of disanalogy and points of disanalogy weaken an argument much faster than points of analogy build it up. Hume builds up a whole list of points of disanalogy of two sorts:
the argument doesn't prove qualities that we want the argument would prove qualities that we don't want.
Examples: watches are usually made by groups of people, rather than single designers; watches are the result of trial and error, not once-for-all design; watches are made by physical, imperfect beings; watches are refashionings of material, not creations out of nothing; watches keep going without any interference from the original manufacturers; and so on
Hume also considers the effect of evil on the argument from design.
This has two effects: it lessens the likelihood of purposive design; and it shows how far the argument is from proving a God of perfectly good moral character.
Now a probabilistic argument can establish only a probability; the question is, how high a probability? Normally anything less than 50% makes the argument worthless: flipping a coin would do as well. Given the weakness of the analogy and the unlikelihood that every part of nature is purposive, it‟s hard to claim that the probability of the analogy argument is even close to 50%. Given a well-supported alternative hypothesis which renders the phenomena probable, and which appears a better hypothesis abductively than the design hypothesis, the entire design argument is very weak.