Professor Bradly Monton gave us a fascinating talk on March, 30th, 2017, at the Big Lecture Hall in School of Philosophy. The title of his talk was “Atheism and Thermodynamics”. Doctor Darrell Rowbottom, Professor and Head in Department of Philosophy at Lingnan University, was the commentator.
At the beginning, Prof. Monton clarified what is the theism entertained in his mind. Instead of the old platitude that God exists, theism, when properly understood, should be a more modest hypothesis: The probability of the proposition that God exists is high enough; or, say, God probably exists. Atheism is correspondingly the denial of theism. Then Prof. Monton announced that although he was an atheist, he was just going to establish a philosophical argument for theism in this talk.
It is a scientific fact that the whole universe is more probable in a high-entropy state. While in the galaxy where we live, most things seem to be highly organized, which means that the galaxy, as a part of the whole universe, is in fact in a low-entropy state. Here we face a tension between our theoretical science and our empirical observations. Ludwig Boltzmann, an Austrian physicist and philosopher in 19th century, whose greatest achievement was in the development of statistical mechanics, gave us an explanation: Even the whole universe is in a high-entropy state, there might be stochastic fluctuations with lower entropy. Our low-entropy galaxy is just a large fluctuation. Given that the size of the whole universe is definitely enormous, the occurrence of such a huge fluctuation is possible after all, even if this is not very probable.
So far so good. But consider the following possibility: A human brain, with some extra conditions for it to persist over a period of time perhaps, randomly forms out of star dusts in a corner of the universe. As a matter of pure accident, it happens that you and the brain share the same experiences, memories, beliefs, desires, and other non-factive mental states; in another word, you cannot tell whether you are such a brain from your own perspective. Let’s call this brain as a Boltzmann’s brain. A Boltzmann’s brain is of course a fluctuation in the universe. But intuitively, it is a small fluctuation—smaller than our galaxy as a huge one. Since the whole universe is in a high-entropy state, the possibility in which you are merely a Boltzmann’s brain is more probable than the possibility that you are an evolved normal person living in a big galaxy.
However, if God exists, we will have a different picture! For by definition, God is omnipotent and omnibenevolent. Is the obtaining of the possibility in which you are an unfortunate Boltzmann’s brain undergoing a series of illusions or hallucinations really consistent with His power and benevolence? I’m afraid that it is not. It is more probable that you are a normal person when God exists. Prof. Monton therefore concluded his argument with the premise that you are a normal person rather than a Boltzmann’s brain. On the basis of this undeniable premise and the information introduced so for, you have good inductive reason to accept the theist hypothesis, namely, God probably exists.
We have seen the crucial claim that you are more likely to be a Boltzmann’s brain (unless God exists) can be derived in the light of Boltzmann’s explanation for the tension mentioned above. Nevertheless, Boltzmann’s explanation is itself controversial. Prof. Monton told us that most contemporary physicists and philosophers of physics believe a rival explanation provided by the alleged ‘past-hypothesis’, according to which the early universe was wholly in a low-entropy state. He briefly rejected the past-hypothesis on his behalf. While a predictable fact was that this rejection remained to be no less controversial. Moreover, even though the past-hypothesis is untenable, it doesn’t follow that Boltzmann’s original explanation is right.
In his comprehensive comment, Prof. Rowbottom attacked Prof. Monton’s argument; and, as you can guess, he focused fire on the claim that you are more likely to be a Boltzmann’s brain (unless God exists). Boltzmann’s ideas might be deemed as outdated. Whether we should accept his explanation within the theoretical framework of modern physics is dubitable. Hence, whether Prof. Monton’s philosophical argument is successful depends mainly on concrete physical views. It’s a great lesson revealed in this wonderful talk I believe. (By Jin Zeng)