Notes on Peter van Inwagen's Discussion of the Fine-Tuning Design Argument

Van Inwagen’s Criticisms of the Design Argument
-Note: Van Inwagen only discusses the design argument from the fine-tuning of the universe.

-Objection 1: Chance
-Every possible combination of values for the fundamental constants of nature is equally improbable.
-But, given that there is a universe, some combination or other had to obtain.
-It’s just that, by chance, the values of the constants of the actual universe allow life to arise.
-So we shouldn’t be surprised that the actual combination obtained.

-Van Inwagen’s reply:
-It is unreasonable to say that something obtained by chance whenever (i) it is just one among a large number of possibilities, (ii) there is a possible explanation for why it obtained that would be a good one if true, and (iii) no parallel good explanation exists for any of the other possibilities.
-But this is true of the values of the fundamental constants of nature in the actual universe!
-The combination of values of the actual constants of nature is just one among an (actually) infinite set of other possible combinations)
-The explanation that the values of the actual constants were intentionally assigned by an intelligent agent would be a good one if true.
-And no parallel good explanation exists for any of the other possible combinations of value assignments to the constants of nature (for they would all lead to a universe without life, which doesn’t seem surprising or in need of explanation).
-So it is unreasonable to attribute the combination of values of the constants of nature to chance until we have other reason for thinking otherwise.
-The “firing squad” illustration


-Objection 2: Necessity
-The values of the fundamental constants of nature are necessary – they couldn’t have been otherwise.
-But if so, then we need not postulate a designer as the explanation

-Van Inwagen’s Reply:
-We have no reason to believe that this is true, and good reason to think it’s false
-The “cube” illustration

-Objection 3: Perhaps we’re “mice in the walls of the cosmos”
-Even if we must conclude that the universe is designed, it doesn’t follow that it’s designed specifically for our sake.

-Van Inwagen’s reply: Even if it’s true, this argument still grants that the universe was designed.


-Objection 4: There is an equally good, rival explanation of the fine-tuned universe
-The fine-tuning for life would be equally well explained if our universe is embedded in a vast “sea” of infinitely many other universes.
-Imagine a natural process that is a “cosmos generator” that continually pumps out universes – perhaps something like a giant quantum field
-Each time it pumps out a universe, it gives a random combination of values to its fundamental constants of nature
-So on this hypothesis, infinitely many of other universes – or at least lots and lots – exist, and each one has a different set of combinations of fundamental constants of nature
-Most of them have no life, since only a few possible combinations of values of the constants are life-permitting
-But the fact that there is life in this is one of those few cosmoi – out of the trillions upon trillions of cosmoi that exist -- that has the “right” combination of values
-This hypothesis is just as good as the hypothesis of intelligent design
-So we have no persuasive reason to prefer the hypothesis of intelligent design

-Objection: OK. But even if such a “cosmos generator” existed, it would be an exceedingly complex object, with laws and constants that would themselves require a designer. But if so, then the hypothesis only pushes the need for a designer back one step – for a designer of the laws and constants of the “cosmos generator”
-Reply: Let’s just stipulate that the cosmos generator has its laws and constants of necessity, i.e., that there is only one possible set of laws and constants for the cosmos generator. It’s not important that this stipulation is true; it need only be a hypothesis with no features for which we have independent reason to think false or impossible. This is both true of this hypothesis and the designer hypothesis.

-Van Inwagen’s Conclusion: Even though we’re unable to determine which hypothesis is true, we have still reached a substantive metaphysical conclusion: something accounts for the fine-tuning of the universe – it’s extremely unreasonable to think that it’s a brute fact that its fundamental constants have these extremely improbable life-permitting values, as the early objections demonstrate. However, we can’t reach a definitive conclusion as to whether the thing that accounts for the fine-tuning of our universe is an intelligent designer or a multiverse.