Original author's comments on this response.

ARTHUR SHAPIRO HAS JUST argued that X does not entail Y, where X is biological evolution of the Darwinian or neo-Darwinian stripe, and Y is any particular position on the ultimate origins of life or the universe. To this I offer a hearty Amen. But I also ask, So what? As a mathematician I've had plenty of experience in the logic of entailment-every theorem is entailed by some relevant set of mathematical axioms As a philosopher who works in the logic of conditionals, I'm aware how entailment works outside mathematical contexts. Entailment is the strongest logical connection by far. To say that X entails Y is to say that it's impossible for X to be true and Y false. Alternatively, Y is necessary given X. Thus, to say that X does not entail Y is to say that it is possible for X to be true and Y false. But since Shapiro leaves Y completely open-ended on the questions of origins, to say that biological evolution does not entail any account of origins, be it theistic, materialistic, or whatever, is simply to say that biological evolution is logically compatible with any number of positions on the origin of life and the universe.

Given what is meant by logical entailment-and this is the sense in which Shapiro is using it-I must agree with his claim. Moreover, Shapiro's claim has empirical support: individuals with widely divergent views on origins have made their peace with, or (if you will) have surrendered to, neo-Darwinism. Certainly this is true of "scientistic atheists" like Will Provine. But it is also true of notable theists like Richard Swinburne, who even when writing on teleology and design admits the central claims of neo-Darwinism:

Complex animals and plants can be produced through generation by less complex animals and plants . . . and simple animals and plants can be produced by natural processes from inorganic matter.{1}

So what? Suppose I place Al and Bob in a room, lock it, reopen it an hour later only to find Al lying on the floor in a pool of blood, with Bob standing over him holding a smoking gun. Denote this scenario by X. Let Y denote the claim that Bob shot Al. Does X entail Y? Well, no. Al may have been suicidal and shot himself. Bob tried to prevent this and is now holding the gun which he was too late in taking away from Al. Suppose, however, we know that Bob and Al are mortal enemies, and that Al has no suicidal tendencies. With this background knowledge, does X entail Y? Again the answer is No. There might be a trap door in the room. Perhaps an enemy of both Al and Bob used the trap door to enter the room, shoot Al, and then place the gun in Bob's hand so as to frame Bob.

If this story appears fanciful, if I appear to be veering from the path of common sense, it is because the logic of entailment cannot distinguish between the banal, the bizarre, and the ridiculous. It can distinguish only between the possible and the impossible. The circumstantial evidence for Bob's killing Al may be excellent if a video camera in the room happens to record Bob shooting Al, there will even be direct evidence for Bob shooting Al. But no amount of empirical evidence will entail Bob shooting Al. Bob's double might actually have shot Al. Bob's enemy might have rigged the video camera so that it only appears that Bob shot Al. I am not suggesting that our reason for believing that Bob shot Al becomes inferior because no evidence can entail this claim. Entailment is simply too strong a logical notion to apply in most matters of fact. In particular, it is the wrong philosophical tool for investigating the relation between Darwinism and origins.

It is here that Shapiro and I part company. Shapiro argues, and I quote,

Biological evolution is no more inconsistent with religion than are other sciences, and . . . the attacks on it specifically are best understood in sociological and political, not philosophical, terms.

In philosophy, implication is a more general notion than entailment. The scenario of Al and Bob locked in a room together with some appropriate background assumptions would implicate that Bob had murdered Al, but it wouldn't entail that Bob had murdered Al. Implication includes entailment, and therefore addresses questions of possibility and necessity. But implication also addresses questions of uncertainty, partial evidence, and probability. X can implicate Y without X having to force Y to be true under all possible circumstances. X can implicate Y. X can be true, but Y might still fail. Any lawyer will appreciate this point. As an aside, let me mention that this is one reason why I appreciate Phillip Johnson's work of weighing neo-Darwinism in the legal balances. A strict logico-deductive argument will never settle the creation-evolution debate.

I've said that Shapiro ignores the epistemological question of what implications exist between neo-Darwinism and theology. This is true in that he admits no implication other than entailment. Nevertheless, without assigning it any epistemological weight, he does mention a significant implication. Commenting on natural selection Shapiro notes,

Darwin's great intellectual triumph was to provide a mechanism, natural selection, that could account for . . . the appearance of design without invoking a Designer. Clearly, the availability of such a mechanism would gladden the heart of anyone who for whatever reason wished to banish God from the universe. But it itself could not banish God from the universe. If the mechanism works, if it is proven valid and sufficient, then it renders God simply redundant in that context. But that is not to say that it disproves His existence; it merely makes it a teensy bit less necessary for explanatory purposes.

Now I agree wholeheartedly that this implication is correct. Swinburne endorses it as well. I quoted Swinburne earlier as supporting the fundamental thesis of neo-Darwinism, viz., that "complex animals and plants can be produced through generation by less complex animals and plants . . . and simple animals and plants can be produced by natural processes from inorganic matter." Swinburne makes this claim at the same time he is advancing an argument from design. How can he do this? By looking to cosmology instead of biology. Indeed, he admits that Darwin has banished design from biology.

Now Shapiro doesn't think that the implication "if neo-Darwinism is right, then design is an unnecessary explanatory device" has much riding on it theologically. For Shapiro it is enough that the existence of God remain secure. As Shapiro has rightly observed, Darwinism entails nothing about the existence of God. For theology, however, there is more at stake than simply the existence of God. The nature of this God, his relation to the world, and his causal powers to affect the world are part and parcel of any theological position.

In terms of the logic of entailment it makes no big difference to the existence of God whether Darwin was right or wrong. But in terms of the logic of implication it can make a big difference to a theological position whether Darwin was right. Shapiro's theology is certainly at peace with Darwin. A strictly pietistic theology can without much difficulty make peace with Darwin. A deistic theology can readily make peace with Darwin. Only a theology so obtuse as to insist on biblical inerrancy cannot make peace with Darwin; at least this is the impression Shapiro leaves.

What are the implications of Darwinism for theology? Shapiro has correctly argued that Darwinism does not entail any of the isms that contend with religion. Shapiro has also argued, again correctly, that Darwinism implicates the redundancy of design. Phillip Johnson (I believe rightly) takes this implication a step further, viz., Darwinism implicates naturalism. As Johnson puts it,

"Evolution" contradicts "creation" only when it is explicitly or tacitly defined as fully naturalistic evolution-meaning evolution that is not directed by any purposeful intelligence.

In closing this response, I feel it necessary to say a few words in defense of Phillip Johnson. Shapiro has charged Johnson with "making the same vulgar errors as appear routinely in the presentations of professional creationists." There is only one error I can see Shapiro referring to, and that is the error of claiming that Darwinism entails naturalism (a claim that is false simply because God can always be maintained as a useless appendage in any world view). That Johnson never claimed such an entailment should have been obvious to Shapiro, since Johnson as a lawyer is in the business of weighing evidence subject to uncertainties, and not in the business of entailments involving necessary connections. Shapiro's charge therefore cannot be supported.

Shapiro's criticism of Johnson, however, fails in a more serious way. Shapiro claims that Darwinism does not entail naturalism. Johnson claims that Darwinism implicates naturalism. Both are right. Nevertheless, I would claim that Johnson's concern in writing Darwin on Trial was not primarily with X entailing or implicating Y, where X is Darwinism and Y naturalism, but Y implicating X. The reverse implication is really the important one. Sure, Darwinism gives God less to do and therefore implicates naturalism. But naturalism in turn needs something like Darwinism to keep it viable.

As Alvin Plantinga puts it, if you accept naturalism, Darwinism is the only game in town. Plantinga claims an implication from naturalism to Darwinism. Johnson's work properly speaking is devoted to this implication. As a lawyer concerned with how ideological agendas-and naturalism is one such agenda-influence the courts, it is only natural for Johnson to concentrate on this implication. Shapiro has therefore missed the boat twice. The question was never whether X entails Y. It was always obvious that X implicates Y. The central question was how Y implicates X, i.e., how naturalism manages to keep Darwinasm afloat. Indeed, Darwinism needs more than scientific facts to keep it afloat.

Copyright © 1994, 1997 Foundation for Thought and Ethics.

Copies of the book Darwinism: Science or Philosophy are available from:

Email this to a friend