Sean Carroll has been instrumental in sparking (and keeping aflame) my my interest in physics. He’s an accomplished academic, but he does a ton of writing and lecturing for the layman. He’s also one of the few serious scientists who takes philosophy seriously and considers the philosophical implications of his work. I was first introduced to that side of him in his writing on the foundations of quantum mechanics, but I’ve been thinking a lot about cosmology/the origin of the universe/the anthropic principle lately, so when I came across Why is There Something, Rather than Nothing?, I knew it was the perfect candidate for my next post.
Carroll begins the article by making a key distinction between two different versions of what we may mean when we ask “Why is there something, rather than nothing?”. The first, “What mechanism brought the universe into existence?”, he characterizes as a question that could reasonably be the subject of scientific inquiry. The second, “What reason explains why anything exists at all?”, demands a little more thought, and an inquiry into how the modern scientists thinks about reasons at all.
In essence, science does not think the language of “causes and effects” appropriately describes reality. Rather, reality is described by the laws of physics and the relations and patterns that emerge therefrom. Certain “why” questions (like why did the baseball break the glass window) can be described in terms of causes and effects, but when we’re looking at reality as a whole, it’s just not the right way to think about it. Still, there might be some underlying principle that explains why the universe has the laws of physics it has, etc., and in that sense of “why”, we can dig productively dig in. Even then, however, we could always ask a deeper “why” question into infinite regress. If we want to avoid infinite regress, we need to look for (i) an level of the explanatory regress that is necessarily true, (ii) a level of the explanatory regress that we accept as brute fact, or (iii) something in between that we take as a satisfactory explanation due to satisfying some criteria or another.
This leaves us (so says Carroll) with five possible answers to why the universe exists: (i) it was created, (ii) it is one of many (infinite?) realities in a “metaverse”, (iii) its existence follows some underlying principle that necessitates its existence as opposed to other conceivable universes, (iv) its existence is necessary given the logical incoherence of “nothingness”, and (v) it just does (brute fact).
Carroll returns to address each of these five possibilities at the end, using the sections between to arm the reader with the tools necessary to assess each possibility. The discussion gets a bit technical at times (at least for a poor liberal arts boy like myself), but a lot of it is spent on the question of whether (logically) the universe’s existence requires something external from itself to bring it into existence, or whether it can (as Carroll puts it) “simply be”. He first demonstrates that our current best scientific theories allow for both the possibility that the universe has always existed, and that it came into being, then arguing that if even there was a beginning to the universe, it can be completely described by laws of nature without the need to appeal to an external creator.
I know I’m not doing justice to his arguments, so I’ll wrap up with a few other interesting observations:
- Answering big philosophical questions with appeal to our most complicated, abstract scientific theories is a tricky business. A lot of Carroll’s arguments rely (in small or large part) on incomplete/unproven theories, such as quantum gravity. I don’t think this pokes a hole in any argument Carroll makes though. Just a thought.
- Examining deeply the notion of cause and effect as applied to our reality is really powerful in dispelling theistic arguments about the existence of the universe. For example, enlightenment-era philosopher Gottfried Wilhelm Leibniz famously argued that everything, including the universe itself, must have an explanation, so ultimately, and in order to avoid infinite regress, we find our explanation in a necessary being (God) – this was his “Principle of Sufficient Reason”. As Carroll points out, “Once we think of the laws of nature as describing patterns rather than causal forces, and the notion of cause and effect as being appropriate to higher-level emergent descriptions of the world rather than the fundamental level, the [Principle of Sufficient Reason] loses its luster.”
- Along those lines, even if the existence of a world hospitable to life presents a fine-tuning problem, it seems odd that a creator would put us in this tiny corner then bother to make an incomprehensibly vast amount of other stuff.
Carroll ultimately concludes that if we want to approach questions about the universe from a scientific perspective, “why is there something rather than nothing” doesn’t seem like a productive question. I kind of agree.
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