Notes on Christianity and the Many Worlds Interpretation of Quantum Mechanics (1998)
Philip Dorrell (1995) makes a number of claims about Christianity and “Many Worlds Interpretation” (MWI) of quantum mechanics. I find some of those claims objectionable, and some of them worth adding to.
Rejection of MWI as Christian Doctrine?
Dorrell starts out his paper by alleging the existence of “a new semi-official Christian Doctrine” according to which the MWI is false. Personally, I would like to see quotes and references, indicating that Christians reject MWI as a matter of doctrine. I have never seen anyone, Christian or not, offer reasons to reject MWI that deviate from the standard reasons secular physicists and philosophers of physics (Albert, 1993; Barrett, 1997) give. If there is a trend arising, in which Christians state out of hand, as a pure matter of doctrine, that MWI is false, I am unaware of such a trend, and would like to see evidence of its existence.
Does MWI Generate Theological Conundrums?
Personally, I don’t see why MWI, even if it were (or is) the correct way to think about quantum mechanics, would raise very severe "theological conundrums." Dorrell asks, for instance, whether our souls, Heaven, Hell, and God, split along with the rest of the universe when the universe splits. But presumably neither souls, nor Heaven, nor Hell, nor God, are physical things, describable by wave functions, so it would stand to reason that none of them would split with the physical world. This leaves the minor problem of which branch any given soul travels into when the physical world splits, but this is hardly a conundrum on the scale of God’s alleged atemporality.
Does MWI Preserve Determinism?
According to Dorrell, MWI preserves determinism. But this is only so for the wave function of the universe as a whole – as far as our experience goes, indeterminism still rules in MWI, because there is no way we can predict which branch of a splitting universe we will end up experiencing after a measurement has occurred. Alternatives to quantum mechanics like Bohm’s theory are more successful at saving a pervasive determinism.
MWI and the Origin of Life
Initially, I viewed Dorrell’s MWI response to the improbability of the origin of life with suspicion, because he characterizes MWI as positing a split between universes only when a measurement takes place. But without any specification of what a measurement is (a problem which MWI in and of itself does not address), we are left with the possibility that measurements are things that can only happen after intelligent life has already come about (whether because measurement is interaction with consciousness, or because measuring devices are things that can only be constructed by intelligent entities). However, under the version of MWI championed by David Deutsch, all of the different types of universes that are physically possible are already instantiated somewhere. Even universes with a probability of zero may be instantiated somewhere, if the total set of universes is infinite. I won’t go into any details here, because this version of MWI appears to have severe problems with it (Albert, 1993), but it is worth noting that if it were correct, then Dorrell’s conclusion about the ineffectiveness of improbability arguments against the origin of life would be correct, even if the only way life could form were by a random, all-at-once aggregation of subatomic particles into a fully formed adult human.
MWI and Occam’s Razor
Dorrell correctly notes that Occam’s razor does not necessarily have any bearing on the number of entities a theory includes – the razor’s sharpness depends on a more generalized measure of simplicity. On the other hand, simplicity cannot necessarily be gauged purely by the number of postulates in a theory, either. For instance, interpretations that feature a nonlinear recasting of Schrodinger’s equation have as few postulates as MWI, since they too fail to contain any separate collapse postulate, but surely an interpretation featuring a nonlinear dynamics is not as simple as an interpretation that does the same work with only a linear equation (as MWI is supposed to do).
Of course, however many postulates one has, and however complicated one’s postulates are, one must at least have enough postulates to get the job done. The splitting-worlds version of MWI, however, does not even specify what it takes to cause the universe to split. As such, it inherits the measurement problem from the Copenhagen Interpretation – simpler than the Copenhagen Interpretation or not, this will not do. In contrast, an interpretation that posits a single, nonlinear dynamics instead of a sharp divide between linear dynamics and nonlinear collapses (or, analogously, splittings of the universe) provides a full description of what is supposed to be happening.
Would God Prefer Many Worlds to a Single World?
As Dorrell notes, God may prefer to create a universe which can split up into others (or, in the Deutschian view, create a full ensemble of universes right at the outset). On the other hand, God may prefer to create a single universe in which the physical laws make the spontaneous appearance of life somewhere in the universe probable or certain (minimum complexity or no, our universe may be precisely of this type). Or God may prefer to create universes generally inhospitable to life one by one until life arises. Or God may prefer to create a fully formed universe, complete with fully formed life and the mere appearance of age. Who knows what God would prefer? It isn’t as if any of the above options are more difficult than the others, for an omnipotent God.
I would like to offer my own (somewhat toungue-in-cheek, although I’m sure there will be those who will take it very seriously) suggestion for why God might like some type of MWI, or something vaguely like an MWI. Suppose that actual awareness is contingent upon the posession of a soul. Now suppose further that the souls are divided up among the total set of universes (or made to divide up via world-splitting) so that there is at most one soul in each universe (the rest of the "people" in the universe are automatons that behave as though they were conscious). Now suppose that the distribution of souls is governed in such a way that no soul has gratuitous pain inflicted upon it. What happens to the problem of evil?
- Albert, David Z. 1993. Quantum Mechanics and Experience. Cambridge, Massachusetts: Harvard University Press.
- Barrett, Jeffrey A. 1997. “On Everett’s Formulation of Quantum Mechanics.” Monist 80(1): 70-96.
- Dorrell, Philip. 1995. “God and the Many Worlds Theory.”