In my last post, I reviewed Sabine Hossenfelder’s Existential Physics: A Scientists Guide To Life’s Biggest Questions. However, I failed to comment on one of its essential passages concerning time, death, and meaning. It involves the block universe or eternalism, the Einsteinian idea that “there is no basis for singling out a present time that separates the past from the future because all times coexist with equal status.”1 Hossenfelder explains what this means with this simple image,
… once your grandmother dies, information about her—her unique way of navigating life, her wisdom, her kindness, her sense of humor—becomes, in practice, irretrievable. It quickly disperses into forms we can no longer communicate with and that may no longer allow an experience of self-awareness. Nevertheless, if you trust our mathematics, the information is still there, somewhere, somehow, spread out over the universe but preserved forever. It might sound crazy, but it’s compatible with all we currently know.
In other words, as Hossenfelder writes later,
According to the current laws of nature, the future, the present, and the past all exist in the same way. That’s because, regardless of what you mean by exist, there is nothing in these laws that distinguishes one moment of time from any other. The past, therefore, exists in just the same way as the present. While the situation is not entirely settled, it seems that the laws of nature preserve information entirely, so that all the details that make up you and the story of your grandmother’s life are immortal.
Now I have been aware of the idea of the block universe since I was a graduate student in Richard Blackwell‘s seminar “Concepts of Time.” I also mentioned how eternalism was significant in my latest book, Short Essays on Life, Death, Meaning, and the Far Future,
Some might still find it distressing to think that their individual consciousness, despite its role in creating cosmic meaning, will have faded into oblivion long before new heights of meaning are reached. But maybe this view of time is mistaken and future meaning is already a part of us, and we are a part of it… now. After all, Einstein’s theory of special relativity implies that objects and events from the past, present, and future all exist eternally and are all equally real.
I didn’t explore the idea further but Hossenfelder has reminded me how such a pursuit might be fruitful. I have hesitated to explore this idea further because 1)I don’t have the mathematical background to really understand physics at more than a basic layperson level and 2) I have always found it hard to reconcile the strong intuition of time’s passing (presentism) with Einstein’s block universe. Let me explain.
Much of modern science is counterintuitive. Who really can conceptualize atoms much less subatomic particles? Other than experts, who really understands quantum mechanics or relativity theory? I can say that the electrons in my hand are repulsed by the electrons in the wall thus preventing them from passing through, and I’ve said this in class. But as a non-expert, I have only a vague understanding of such ideas.
Now I accept all this because I understand the power and truth of modern science but eternalism has always been hard to grasp. My parents and grandparents just seem as dead to me as I will seemingly be to my children and grandchildren. It is just a hard intuition to avoid. Now again I know that intuition is a poor guide to truth. If it were I’d think that the planet was flat and not moving beneath my feet—both ideas obviously false but quite intuitive. But the past and future being as real as the present—that’s a hard idea to feel in your bones.
Of course, Hossenfelder and others continue to remind me of this and I’ll hopefully have time to think more about this in the next few years. I’d better do so soon because it feels as if I’m running out of time!
1.”The quantum theory of time, the block universe, and human experience,” in The Philosophical Transactions of the Royal Society A, Joan A. Vaccaro, 28 May 2018.