Sean M. Carroll quotes

Sean M. Carroll is an American theoretical physicist, author, and science communicator known for his work in cosmology and quantum mechanics. His research explores the origins and nature of the universe, as well as the foundations of physics. He actively promotes public understanding of science through books, lectures, and podcasts. Here are 46 of his quotes:

The fact that you can remember yesterday but not tomorrow is because of entropy. The fact that you're always born young and then you grow older, and not the other way around like Benjamin Button - it's all because of entropy. So I think that entropy is underappreciated as something that has a crucial role in how we go through life.

Sean M. Carroll

If our local, observable universe is embedded in a larger structure, a multiverse, then there's other places in this larger structure that have denizens in them that call their local environs the universe. And conditions in those other places could be very different. Or they could be pretty similar to what we have here.

Sean M. Carroll

Meaning in life can't be reduced to simplistic mottos. In some number of years I will be dead; some memory of my time here on Earth may linger, but I won't be around to savor it.

Sean M. Carroll

In contrast to the arbitrarily complicated evolution of a (nonintegrable) classical system, all a quantum state ever does is move in circles.

Sean M. Carroll

The mystery of the arrow of time comes down to this: Why were the conditions in the early universe set up in a particular way, in a configuration of low entropy that enabled all of the interesting and irreversible processes to come?

Sean M. Carroll

All of my advice comes from remembering what I did wrong and then telling people not to do it. ... Don't wait to read the most recent research papers. ... Wonder how you could do better. ... Do your own research projects. Take the initiative. ... Ask your own questions - try to answer them. ... At some point you stop being a student and you start being a scientist. ... And it's a completely different skill set ...

Sean M. Carroll

I don't want to give advice to people about their religious beliefs, but I do think that it's not smart to bet against the power of science to figure out the natural world. It used to be, a thousand years ago, that if you wanted to explain why the moon moved through the sky, you needed to invoke God.

Sean M. Carroll

Even in empty space, time and space still exist.

Sean M. Carroll

If time travel were possible, you still wouldn't be able to change the past - it's already happened!

Sean M. Carroll

I'm trying to understand cosmology, why the Big Bang had the properties it did. And it's interesting to think that connects directly to our kitchens and how we can make eggs, how we can remember one direction of time, why causes precede effects, why we are born young and grow older. It's all because of entropy increasing.

Sean M. Carroll

When exactly does an observation occur? ... What were the laws of physics doing before there was anyone measuring things? And what do you mean by a measurement, anyway? Does it have to be a consciousness human being? ... Can a rock or a virus or an earthworm do an observation?

Sean M. Carroll

Inflation is a simple idea: imagine that the universe begins in a tiny patch of space dominated by the potential energy of some scalar field, a kind of super-dense dark energy. This causes that patch to expand at a terrifically accelerated rate, smoothing out the density and diluting away any unwanted relics. Eventually the scalar field decays into ordinary matter and radiation, reheating the universe into a conventional Big Bang state, after which things proceed as normal.

Sean M. Carroll

There probably are more forces than we know about, but they're only going to be of direct interest to physicists, I'm afraid. No tractor beams.

Sean M. Carroll

The "reasons” and "causes” why things happen, in other words, aren't fundamental; they are emergent. We need to dig in to the actual history of the universe to see why these concepts have emerged.

Sean M. Carroll

We are looking for a complete, coherent, and simple understanding of reality. Given what we know about the universe, there seems to be no reason to invoke God as part of this description.

Sean M. Carroll

All the stuff we've ever seen in the laboratory, all the kinds of particles and matter and energy, that only makes up 5 percent of our universe.

Sean M. Carroll

I'm trying to understand how time works. And that's a huge question that has lots of different aspects to it.

Sean M. Carroll

Science isn't just about solving this or that puzzle. It's about understanding how the world works: the whole world from the vastness of the cosmos to the particularity of an individual human life. It's worth thinking about how all the different ways we have to talk about the world manage to fit together.

Sean M. Carroll

The arrow of time doesn't move forward forever. There's a phase in the history of the universe where you go from low entropy to high entropy. But then, once you reach the locally maximum entropy you can get to, there's no more arrow of time.

Sean M. Carroll

A full understanding of what happens in our everyday lives needs to take into account what happened at the Big Bang. And not only is that intrinsically interesting and just kind of cool to think about, but it's also a mystery that is not given much attention by working scientists; it's a little bit underappreciated.

Sean M. Carroll

Naturalism says that we were not put here for any purpose. But that doesn't mean there isn't such thing as purpose. It just means that purpose isn't imposed from outside. We human beings have the creative ability to give our lives purposes and meanings.

Sean M. Carroll

The simplest way out of the puzzle of time travel is to say that it can't be done. That's very likely the right answer. However, we don't know for sure.

Sean M. Carroll