In my recent debate with David Papineau about materialism and dualism, much of our discussion turned on the question of causal closure. Materialists generally argue that dualism of mind and brain is not possible because of causal closure — by which they mean that all physical effects have physical causes. They generally extend this argument to deny the existence of God. They argue that the fundamental cause of everything is just the material universe and that causation of the universe by God would violate causal closure and would be unintelligible. To the question “What caused the universe?” atheists and materialists argue that the universe is not an effect but exists in its own right and therefore does not need a cause.
To buttress their argument, materialists claim that modern physics affirms causal closure.
They Couldn’t Be More Wrong
As I noted, causal closure means that all physical effects have physical causes. Modern physics is replete with examples of physical effects that have no physical causes and cannot have physical causes. Consider:
The Big Bang: The Big Bang is clearly a physical effect — it is the ultimate physical effect (the beginning of the universe) — but it is just as obvious that it has no physical cause, because the whole notion of a physical cause is difficult to apply to the beginning of time. The singularity that gave rise to the Big Bang is prior to the universe not in time but in the sense of a causal chain. And the singularity is not itself a physical cause, because in general relativity is undefined.
Materialists will and do argue that the universe is the ground of existence and needs no cause, but this is wrong on two accounts. First, as Thomas Aquinas clearly showed in his cosmological arguments in the first Three Ways, the ground of existence needs to be pure actuality without any potentiality and needs to be self-existent without any contingency. But the universe and everything in it is full of potentiality and contingency and could not be the ground of existence.
Second, if one accepts the assertion that the entire universe exists without cause, science and even everyday life are rendered nonsensical. If all that exists came into being without a cause, why infer that anything in daily life or in scientific investigation needs to have a cause? If one accepts the principle that the entire universe needs no cause, one accepts magic and incomprehensibility in all of life and of course in science.
As G. K. Chesterton said in a slightly different context, you can believe the universe has no cause, but if you really believe that you can’t believe anything else. Your belief renders everything nonsensical.
The existence of the universe from the Big Bang violates causal closure.
Singularities in black holes: Singularities in black holes obviously cause many physical effects — black holes distort space time, have enormous effects on surrounding matter, and influence the dynamics of galaxies. However, singularities at the core of black holes are not physical. They represent undefined expressions and field equations of general relativity, and thus cannot in any way be considered physical things or physical causes.
The existence of singularities in black holes violates causal closure.
The field equations of curved space-time: It has been recognized since the early 20th century that the field equations of general relativity when applied to curved space-time violate the principle of conservation of energy. In fact, cosmologists have even developed a mathematical tool — called pseudo-tensors — in an attempt to rig general relativity in accordance with conservation laws. Whatever the value of pseudo-tensors in cosmological investigation, they are ad hoc and only serve to emphasize that general relativity itself entails violation of the conservation of energy in the observable universe.
Of course, if energy is not conserved in our relativistic universe then one can make no sense of the statement that “every physical effect has a physical cause,” because energy can be created and destroyed without account and the bookkeeping between physical effects and physical causes falls apart.
General relativity in curved space-time violates causal closure.
Quantum entanglement: In quantum systems there are pairs of particles that have complementary properties. A classic example would be a pair of entangled electrons with up and down spins. It is a principle of quantum mechanics — that has been amply demonstrated experimentally — that entangled electrons do not have defined spin until one electron is measured, at which time it acquires a spin and its entangled partner acquires the opposite spin.
All of this is of course problematic from the crude perspective of causal closure, but as we will see quantum entanglement is a clear violation of causal closure. This is because measurement of one electron establishes the spin of its entangled partner instantaneously, and the simultaneity occurs regardless of the distance between electrons. If an electron is measured on one side of the universe, its entangled partner on the other side of the universe — 93 billion light-years away — will instantaneously exhibit the corresponding spin. Remember that the doctrine of causal closure states that every physical effect has a physical cause and consider that the acquisition of a discrete spin in an entangled electron is most certainly a physical effect. But the cause of that physical effect — measurement of its entangled partner — cannot be transmitted more rapidly than the speed of light because no physical entity or effect can have superluminal velocity.
The simultaneity of quantum entanglement precludes causal closure.
The Immaterial Mind
There are undoubtedly more examples of violations of causal closure in modern physics, but the Big Bang, black holes, the field equations of general relativity, and quantum entanglement are sufficient examples of the lack of causal closure in nature to render the causal closure argument against dualism in the mind-brain problem ineffectual.
The immaterial mind — that is, formal and final causes — can violate causal closure (understood in a materialist sense as the requirement that every physical effect has a physical cause), just as general relativity and quantum mechanics in modern physics violate causal closure.
The materialist invocation of causal closure to deny dualism of mind and brain is a refuted argument, and it is ironically refuted by the same modern science that materialists claim is the basis for their ideology. Materialism is a woefully inadequate framework for modern science — it offers nothing of value to cosmology, quantum mechanics, or neuroscience, and it does not in any way preclude the dualist understanding of the mind.