Does Quantum Physics Undercut the Kalam Argument?

The Objection from Quantum Physics

In a previous post, I argued that the causal premise in the Kalam Cosmological Argument gains support from an Aristotelian understanding of possibility and actuality. We discovered that if the universe began to exist, then it must have been possible for it to begin to exist. Such a possibility is best understood as a potentiality or power residing in an actual thing – namely, a cause.

In today’s post, I’d like to address an objection to the idea that whatever begins to exist has a cause. By far, the most common objection is that quantum particles seem to pop into existence without any cause whatsoever. Quentin Smith (1993) argues for this view when he writes,

…[Q]uantum-mechanical considerations show that the causal proposition is limited in its application, if applicable at all…[Indeed] [i]t is sufficient to understand causality in terms of a law enabling single predictions to be deduced….[T]hat there are uncaused events in this sense follows from Heisenberg’s uncertainty principle, which states that for conjugate magnitudes such as the position q and the momentum p of a particle, it is impossible in principle to measure both simultaneously with precision.[1]

Quentin Smith, philosopher of physics and religion
Quentin Smith, philosopher of physics and religion

Smith’s argument relies on the idea that causation can be cashed out in term of predictability in principle. Since Heisenberg’s uncertainty principle foils our attempts at making exact predictions about the mechanics of quantum particles, Smith infers that such events are uncaused. But should we accept his view of causation? I can think of two reason why we shouldn’t.

Two Reasons to Discard the Objection

First, Smith’s analysis does not allow for agent causation. When I act freely (say, by raising my arm), my actions are not fully determined by prior events, which means that those actions can’t be fully predicted (even in principle) on the basis of the physical laws that hold at the time of my action.[2] But if agent causation is real,  then Smith’s view should be rejected because it implies that free actions are uncaused – which is false.

Second, quantum events still have causes even if the physical laws that describe them do not yield exact predictions.  For instance, when quantum particles pop into existence within a vacuum, the vacuum itself contains the energy necessary for their existence. The fact that it is impossible for us to predict, with Newtonian precision, where and when these particles will emerge does not imply that they are uncaused. After all, they don’t just pop into existence from nothing at all! Craig (1993) echoes this point when he writes,

“The microstructure of the quantum vacuum is a sea of continually forming and dissolving particles which borrow energy from the vacuum for their brief existence. A quantum vacuum is thus far from nothing.”[3]

What Smith fails to recognize is that causes (like the quantum vacuum) can be necessary for their effects (the formation of particles), even if their effects aren’t fully predictable.  If so, then quantum particles have causes, despite what Smith claims. Therefore, his objection poses no threat to the first premise of the Kalam Argument – namely, whatever begins to exist has a cause.


[1] See Quentin Smith and William Lane Craig, Theism, Atheism, and Big Bang Cosmology. Oxford: Clarendon Press, 1993. p121.

[2] On the nature of agent causation, see William L. Rowe (1987). “Two concepts of Freedom,” in Proceedings and Addresses of the American Philosophical Association Supplement to Volume 61 pp. 43 – 64.

[3] William Lane Craig (1993). “The Caused Beginning of the Universe: A Response to Quentin Smith.British Journal for the Philosophy of Science 44: 623-639.

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