Mike Huemer, one of my favorite philosophers, has given a fascinating argument for an intriguing conclusion: your life will (approximately) repeat infinitely many times over. That means, as he puts it, "[T]here will be a person looking like you, sitting in front of a computer (or phone, or whatever) like the one you're looking at, reading a post containing these words, some time in the distant future."
Huemer's proposal must have crawled into my subconscious because I had a strange dream about it. I dreamed I was in a large house with lots of people. Everyone was doing seemingly pointless things. I then noticed something eerie: some of the people were duplicates! Suddenly, my view began zooming outward so I could see the house from its top. As I continued zooming out, I saw repeat houses. Then repeat cul de sacs. Then repeat mountains and repeat lands. Like a fractal, everything repeated. In that moment, I had the strong feeling that everything is fundamentally meaningless. Then I woke up.
I am not sure what to make of that dream. But it does indicate something about the significance of Huemer's proposal. It relates to the meaning of our lives. Do we have to do everything again? Is there any ultimate point to anything? Why are we alive at all? Huemer's proposal touches on all these questions.
In any case, I want to have a closer look at Huemer's argument. My goal isn't to knock down the argument. In fact, I think his argument brings to light valuable insights, which I want to highlight. At the end, I'll offer an alternative model on which your life doesn't repeat.
So, why think your life repeats? Here's the big picture structure of his argument:
1. Time is infinite in the past. [source]
2. If time is infinite in the past, your life repeats (approximately). [source]
3. Therefore, your life repeats (approximately).
Click the links to see Huemer's discussion of each premise.
Let's have a closer look.
Huemer offers this reason to think the past is infinite: "when you try to imagine the beginning of time, you imagine time coming into existence—first there wasn't any time, then there was—but there couldn't be such an event."
Here is my representation of the argument:
1. A beginning of something requires a transition from a time without it.
2. There cannot be a transition from a time without time.
3. Therefore, there cannot be a beginning of time.
I like this argument. In what follows, I will draw out what I like most about the argument. To do that, I need to say something about the nature of time. I will first give a theory of times on which I think this argument is sound. Then I will give a theory on which soundness is harder to establish. After that, I will share a version of Huemer's argument that I think successfully establishes at least this much: reality never began.
Start with time. Some philosophers say times are states of affairs that stand in temporal relations. (I've said something like that myself in "Tenseless Times".) If that's what times are, then I think the argument is sound. Here is why. Suppose time begins. Then, the state of affairs, <time existing> comes to be. On my understanding of "comes to be," <time existing> then bears the later than related to the state of affairs, <time's not existing>. But then <time's not existing> counts as a time—since it is a state of affairs that stands in the earlier than relation to later states. In other words, some time is prior to the first time, which is absurd. So, time cannot begin.
On this account of times, however, it does not yet follow that time is infinite in the past. For there is another option: time has a first moment, which itself never began. In this case, time is finite yet didn't come to be.
On the other hand, one might think time cannot be finite without coming to be. After all, times are dynamic by nature (one might think). That means times pass along—from non-being to being, then back to non-being (or from non-obtaining to obtaining to non-obtaining). If times are like that, time cannot be finite without coming to be.
However, on this account of time, a new option opens up: time comes from a state of affairs that doen't count as a time. This state of affairs doesn't count as a time because it doesn't pass along. It never came to be. On this analysis, time flows from a timeless state.
This option takes us into deep waters. Some philosophers doubt that a timeless state could be a foundation for temporal states, whereas others think it's our best option. I won't enter that debate here.
Instead, let us swim away from the seaweed of theories of time. When we come back to shore, we can discover a "timeless" version of Huemer's argument standing strong. This version is for the conclusion that reality (at least) never began:
4. A beginning of something requires a transition from a state without it.
5. There cannot be a transition from a state without states.
6. Therefore, there cannot be a beginning of states.
I accept this result: I think reality (of all states) never began. Three reasons. First, I think a beginning of reality would require that something come from nothing, which I think is impossible (source). Second, I think reality divides into the foundational and the dependent, where the foundational portion has the firmest possible grip on existence—and so cannot come into being or go out of being (source). Third, there is the Huemer-inspired argument above. Thanks Huemer!
In conclusion, I agree that reality never began. The implications of this agreement depends on the nature of time. If times pass along (from non-being to being to non-being), then a beginningless reality implies either an infinite temporal past or a timeless source of dynamic states. Alternatively, a state can count as a time without passing from non-being. Then there is the option that some time is first and without beginning.
For the rest of the argument, I shall grant the infinity of the past to see where that takes us.
Here's a reason to think so (from Huemer): "If the universe has always existed, then it cannot be headed in any qualitative direction overall. If it was overall headed toward some state, then it would have long since reached that state, given an infinite past." Huemer adds math to the argument: "we get the eternal recurrence from the Poincare Recurrence Theorem. To apply the theorem, you have to assume, basically, that the universe stays within a finite region." Thus, the universe repeats.
Is that true? I confess that I have a bias: I hope it isn't. As in my dream, endless repeating makes everything seem ultimately meaningless to me. We are then like Sisyphus, who rolls a boulder up a hill that rolls back down, repeatedly forever. I don't want it to be like that.
But, of course, reality isn't always what I want. I want a gold bar in my hand, but there is none.
So what is true? Does everything repeat? I offer a few notes for your consideration.
First, my impression is that the current view among cosmologists is that the universe will expand forever, and so not repeat (source). Disclaimer: I am not a cosmologist.
Second, the mathematical argument seems to hinge on the infinity of the past. I asked a math professor friend, Brian Hall, at Notre Dame about the Poincare Recurrence Theorem. Here's what he said, "I am doubtful that Poincare recurrence would apply to the state of the universe. The system has to be confined to a bounded region of the phase space for the theorem to apply—meaning that both the position and momentum of the particles would have to be bounded. Thus, even for a classical model of the universe with finitely many particles, it is not clear that recurrence applies."
But then Hall added this: "Possibly, if you assume that the universe is already infinitely old and that the particles have not yet flown off to infinity, you could work around this—but only in a classical (non quantum) model of the universe." That makes sense: if the universe has already been unfolding from eternity past, then the universe probably meets the condition of staying within some region.
On the other hand, one might argue in the other direction. Our universe probably doesn't meet the conditions of staying within some region. So, our universe probably hasn't been unfolding from eternity past.
Finally, even if the past is infinite, there is a model on which the universe doesn't repeat. I'll share that next.
I'd like to close by suggesting a model that I think may account for the data points Heumer mentions, but without infinite repetition. The model is inspired by the thought that an infinite past itself calls for a deeper explanation. To my mind, getting a universe to repeat is like getting a needle to balance on its tip. It is surprising that such a thing would happen without any deeper explanation.
Here is a different model. Reality includes a beginningless foundation. From this foundation springs forth new universes, like bubbles in an ocean. Each universe contains its own on-going adventure.
On this model, your life probably doesn't repeat. When you get your boulder to the top of the hill, it doesn't roll back down. Instead, you are ready for the next adventure.
This model allows (though does not ensure) a reason for your existence. Your life is part of a soul-building adventure. In this adventure, your work matters. Your life matters. And not just temporarily. The progress you make won't be washed away; nor will you have to repeat your labor in an endless cycle. Everything you do contributes to an advancing world.
This "advancing world" model takes into account everything we have considered here. It accounts for a beginningless reality by including a beginningless foundation. It also accounts for the improbability of a universe staying within a region by denying that it does. Instead, the foundation produces new universes throughout eternity.
Is this model too good to be true? It depends on the kind of thing you are, and the kind of thing the foundation is. Are you a soul? Is the foundation good? If the foundation is mindless or evil, probably everything will come to ruin, or repeat forever.
I have a book coming out on the foundation of existence (now available for pre-order). In this book, I explain why I think the foundation of existence would have resources to explain every dimension of reality, including minds, matter, morals, mathematics, and reason itself.