Existential Physics: A Scientist's Guide to Life's Biggest Questions

Sometimes the only scientific answer we can give is “We don’t know.

All the hypotheses about the early universe . . . are pure speculation. They're modern creation myths written in the language of mathematics.

For 97 percent of all Wikipedia articles, if you click on the first link and repeat this in each subsequent article, you will eventually get to an entry about philosophy. Philosophy is where our knowledge ends,

I quite like the idea that we live in a computer simulation. It gives me hope that things will be better on the next level.

I don't know if the universe has a purpose, but I would say that there is something more to it, in the sense that the presence of conscious beings is probably something deeper, not just not random. [quoting Roger Penrose]

There are no exact metaphors, not for quantum mechanics and not for anything else, because if they were exact, they wouldn't be metaphors.

According to the currently established 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 all the details that make up you and the story of your grandmother's life are immortal.

Today I think they don't teach the principle of least action in school because then everybody would go and study physics.

If your belief conflicts with empirically confirmed knowledge, then you are not seeking meaning; you are delusional.

Sometimes the only scientific answer we can give is 'We don't know.

Instead of thinking of ourselves as selecting possible futures, I suggest we remain curious about what's to come and strive to learn more about ourselves and the universe we inhabit.

However, they implicitly assume that mathematics itself is timeless, that mathematical truth is eternal, and that logic doesn’t change. This is an assumption that cannot be proved, because what would you prove it true with? It’s one of the usually unstated articles of faith that our scientific inquiry is based on.

If you say “holism,” I hear “bullshit.

So it’s not that consciousness causes the reduction of the wave function but that the reduction of the wave function plays a role in consciousness?

One is that counting microstates and comparing their numbers becomes tricky if a theory has infinitely many microstates, and that’s the case for all continuous-field theories. It is possible to define entropy in those cases, but whether it’s still a meaningful quantity is questionable. It’s generally a bad idea to compare infinity to infinity, because the outcome depends on just how you define the comparison, so any conclusion you draw from such an exercise becomes physically ambiguous.

Physicists should take note that the universal laws they have found might only scratch the surface of so-for-unrecognized complexity. While my colleages think they are closing in on a final answer, I think we've just begun to understand the question.

When Sean Carroll summed up his compatibilist stance with “free will is as real as a baseball,” he should have added “and equally free.

But it doesn’t prime people just to question free will; it primes them for fatalism—the idea that it doesn’t matter what you do.

Our thirst for knowledge is ubiquitous, in both individuals and societies. We want to understand, partly because understanding is useful, but also, I think, out of a primary need to make sense of ourselves and our place in this world.

Popular-science news about quantum mechanics is to me as baffling as it is frustrating. Hand me an equation, and I can deal with it. But if you tell me that quantum mechanics allows one to separate a cat from its grin or that an experiment shows "an irreconcilable mismatch between the friends and the Wigners," I'll back out of the room quietly before anyone demands I explain this mess. I have suffered through countless well-intended introductions to quantum mechanics featuring quantum shoes, quantum coins, quantum boxes, and entire zoos of quantum animals that went in and out of those boxes. If you actually understand those explanations, I salute you, because if I hadn't known already how quantum mechanics works, I still wouldn't know.

While entanglement is indeed nonlocal, it is still created locally.