Sean Michael Carroll (born October 5, 1966) is an American theoretical physicist who specializes in quantum mechanics, cosmology, and the philosophy of science.

[3] He also is currently an external professor at the Santa Fe Institute,[4] and he has been a contributor to the physics blog Cosmic Variance, where he has published in scientific journals such as Nature as well as other publications, including The New York Times, Sky & Telescope, and New Scientist.

Carroll is the author of Spacetime And Geometry, a graduate-level textbook in general relativity, and has also recorded lectures for The Great Courses on cosmology, Time in physics and the Higgs boson.

He began a podcast in 2018 called Mindscape, in which he interviews other experts and intellectuals coming from a variety of disciplines, including "[s]cience, society, philosophy, culture, arts and ideas" in general.

[14] He has also published a YouTube video series entitled "The Biggest Ideas in the Universe" which provides physics instruction at a popular-science level but with equations and a mathematical basis, rather than mere analogy.

His research papers include models of, and experimental constraints on, violations of Lorentz invariance; the appearance of closed timelike curves in general relativity; varieties of topological defects in field theory; and cosmological dynamics of extra spacetime dimensions.

They claim that the universe is infinitely old but never reaches thermodynamic equilibrium as entropy increases continuously without limit due to the decreasing matter and energy density attributable to recurrent cosmic inflation.

[35][36][37] Some of his work has been on violations of fundamental symmetries, the physics of dark energy, modifications of general relativity and the arrow of time.

In 2017, Carroll presented an argument for rejecting certain cosmological models, including those with Boltzmann brains, on the basis that they are cognitively unstable: they cannot simultaneously be true and justifiably believed.

He turned down an invitation to speak at a conference sponsored by the John Templeton Foundation, because he did not want to appear to be supporting a reconciliation between science and religion.

[41] Carroll received an "Emperor Has No Clothes" award at the Freedom From Religion Foundation Annual National Convention in October 2014.

[42] His 2016 book The Big Picture: On the Origins of Life, Meaning and the Universe Itself develops the philosophy of poetic naturalism, the term he is credited with coining.

He wrote ahead of the 2016 United States presidential election that "[Trump] has continually vilified immigrants and foreigners generally, promoting an us-against-them mentality between people of different races and ethnicities" and that he posed a threat to liberal democratic values.

[52][49][53] The participants were Steven Weinberg, Richard Dawkins, Daniel C. Dennett, Jerry Coyne, Simon DeDeo, Massimo Pigliucci, Janna Levin, Owen Flanagan, Rebecca Goldstein, David Poeppel, Alex Rosenberg, Terrence Deacon and Don Ross with James Ladyman.

"[54][55] In 2014, Carroll participated in a highly anticipated debate with philosopher and Christian apologist William Lane Craig as part of the Greer-Heard Forum in New Orleans.

They discussed consciousness, the many-worlds view of quantum mechanics, the arrow of time, free will, facts and values, and other topics including moral realism.