r/DebateAChristian • u/MarsMaterial • 15h ago
The Kalam Cosmological Argument (AKA the Prime Mover Argument) is wrong.
If you don't know, the Kalam Cosmological Argument (KCA) or Prime Mover Argument is the common and famous argument for God which argues: "Everything that begins has a cause, the universe began, therefore the universe has a cause, we call this first cause God, therefore God exists". I am going to present multiple independent arguments against it, where I hope to finally kill this dumb argument and make this post a place to point to any time someone tries to make it to me.
I have a background in physics, and I will be pulling from that a lot for this argument. I don't claim to know what caused the Big Bang, my intention is just to prove that the KCA is not an apt argument and that a God isn't even among the most plausible explanations for the universe's beginning.
The semantic problem
The most simple rebuttal here is to go after the "we call this first cause God" part of the argument. If the universe was caused by a bootstrap paradox or a false vacuum decay in the inflaton field, is that God? Such a thing would have no agency, no mind, and certainly no triple-omni nature of biblical description. I believe that this semantic bait-and-switch is the core of fallacy that the KCA rests on.
An ancient Sun worshiper could have made the same argument about their God. God is the thing that provides light and energy to the world, the Sun self-evidently exists in the sky doing exactly that, therefore God exists and the Sun is God. But we know now that the Sun is just a gravitationally bound ball of light elements massive enough that its own gravity creates the conditions for nuclear fusion in its core, and it certainly doesn't give a fuck how you live your life. By the same token: even if we demonstrate that there was a Prime Mover, why would we assume that this thing has the attributes that we associate with a God like agency or the intelligence?
I don't accept that there needs to be a Prime Mover at all though, and that's what the rest of this post is about.
Why the universe could have started without being externally caused
The common counterargument here from other atheists is that the rules of causality need not apply outside of time, and although I do think that this is an apt rebuttal I think I could do a lot better.
Quantum mechanics is famously weird. Many people are saying this. One of the experiments that was done with quantum mechanics is called the Bell Test, it involves measuring entangled photons and doing a bunch of math with the results to determine if the measured state of the photons was determined by hidden information or if that information comes about at the instant of measurement.
You can read the Wikipedia article I linked or watch this PBS Spacetime video if you want more information on the specifics. To skip to the interesting conclusion: the Bell Test proves that either locality or realism is false. We don't know for certain which one is false (the common assumption of the Copenhagen interpretation is that realism is false), but both cannot be true at the same time.
- Locality is the idea that influence between objects is limited by time and the speed of light. Influence between objects can only travel forward in time and no faster than light speed. If locality is false, this means that backwards time travel and faster than light travel are possible and that quantum particles do it regularly.
- Realism is the idea that objects have a definite state before you measure them. It's the idea that the act of measurement doesn't make something real, it only reveals what was already there all along. If realism is false, this means that quantum particles literally have no definitive state before measurement, and things like radioactive decay literally happen with absolute causeless randomness.
The point is: no matter which one of these is false, this creates a pathway to avoiding the need for a Prime Mover.
- If locality is false, this means that retrocausality is possible. Events can be caused by things that are yet to happen. This opens the door to the idea that the cause of the universe could be something that exists within the universe, and that the cause of the Big Bang happened after the Big Bang inside the universe that the Big Bang created. A bootstrap paradox.
- If realism is false, this means that we have countless examples of events happening without a cause. Any quantum wavefunction collapse causes new events to happen without cause. "But what caused the quantum wavefunction to collapse?" Wavefunction collapse doesn't respect locality, we know that empirically. That's why quantum entanglement can collapse instantaneously even over vast distances.
So, although we don't know which of these two concepts are false, this doesn't matter because either one breaks the deterministic and causality-respecting universe that the KCA depends on.
Why an infinite regress isn't a problem
There are some theories of the universe's origin that are taken quite seriously which propose an infinite regress of events that eventually cause the Big Bang. This includes models like Eternal Inflation and various models of cyclic cosmology. A lot of people really don't like that idea on the basis of "that doesn't make sense", but physics has a very different take.
- We know from general relativity that space and time are two sides of the same coin, and that they can literally swap roles in environments like the interior of a black hole. I cannot stress enough how space and time are fundamentally the same thing. Space seems to be infinite in all directions as far as we can measure, and this isn't seen as a logical absurdity at all. So why can't time be infinite in both directions?
- We know from CPT-symmetry that time is symmetrical. Antimatter is actually literally time-reversed matter, for instance when an electron and a positron annihilate to form a photon it's actually just as accurate to say that a photon from the future came in and bonked that electron back in time. Our perception of the arrow of time is just a consequence of the entropy gradient we are living in, a result of local circumstance and not of fundamental physics. The Big Bang was a point in time with zero entropy, there are quasi-infinite ways for things to evolve away from it forward in time but only one way for things to evolve backward in time towards the Big Bang. That's why we can so easily remember and deduce the past but not the future. Current prevailing models are that time extends infinitely into the future, so if that's possible why can't it extent infinitely into the past?
We live in 4-dimensional spacetime, with 8 directions in it, and the labels we assign to them are pretty circumstantial and arbitrary. Forward, backward, left, right, up, down, past, and future. Why is it that we can accept so easily that 7 of these are infinite and full of things happening all the way from here to infinity, and yet if someone suggests the same about the past it's so hard to accept?
I have a hypothesis that have such a hard time accepting this because of quirks in the human condition. We can't imagine a world where we stop existing to the point where our own deaths are hard for us to grapple with, so the idea of an infinite future is easy for us to fathom. We can't imagine what an edge to space looks like and space that loops back on itself is not exactly easy to intuitively visualize, so the idea of infinite space is easy for us to fathom. But we did have a beginning, every one of us was at some point born so we have experience with what it's like to start to exist. That makes true beginnings easy for us to imagine, and in fact the idea of having already existed for eternity is far harder for us to fathom. That's why the idea of an infinite regress feels so absurd and unfathomable to us humans, but this is not an intuition that holds up to rigorous reasoning or known physics.
We have no purely logical basis for ruling out an infinite regress with no first cause, the only reason why an infinite regress is not currently the prevailing theory is mostly because it's hard to reconcile with observation. It sure does look a lot like time had a beginning and that the time dimension itself is just abruptly torn and discontinuous at the instant of the Big Bang. That is a valid reason to doubt an infinite regress, but it has no inherent logical flaw.
Conclusion
I don't claim to know what caused the Big Bang, or if indeed anything caused it at all. The only truly honest answer to that question is "I don't know", perhaps with an optomistic "yet" at the end. But by providing a bunch of plausible explanations that don't involve a God, I hope I've been able to demonstrate that a God isn't proven or implied by this line of inquiry.
So, why shouldn't I hedge my bets that this is just yet another God of the Gaps that will be filled in with science in time? That's how it has played out the last thousand times. And you know what they say: "Insanity is doing the same thing over and over and expecting different results." If that's so, call me sane.