Invasion of the Boltzmann Brains

Dr. Craig,
I am familiar with the theory of Boltzmann Brains, often given as a response to the atheist multiverse theory. A "Boltzmann Brain" is a universe in which only a single brain exists and nothing else. This universe is supposedly "vastly more likely" to exist than ours. However, I was curious as to how such a brain could form in a world of that size. As I understand the brain, a brain needs a body to survive, and a body needs an external world to interact with, and that external world must be incredibly vast to have produced the body and brain in the first place, and so on and so forth... Doesn't this make the whole Boltzmann Brain theory ridiculous? A brain could not exist in a universe all by itself--at least not a brain as we understand it! The only way to save this theory of a Boltzmann Brain universe seems to be to replace the term "brain" with "mind"--but a mind does not need a universe to exist in, since we have clarified that God is a disembodied mind that exists apart from the universe.
Is the Boltzmann Brain idea of a single-brain universe really as viable as you claim in your popular and scholarly works? Have I misunderstood the theory?
Some serious, scientifically-minded seeker
United States

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