# Sean Carroll American theoretical physicist and cosmologist (b. 1966), Homewood Professor of Natural Philosophy at Johns Hopkins and previously at Caltech, and **the most scientifically credentialed contemporary critic of the cosmological arguments**. He is the principal reason those arguments cannot be defended by citing physics popularisations: he works in the relevant field, and his objections are technical rather than rhetorical. Carroll is a naturalist who describes his position as *poetic naturalism*, the view that the physical world is all there is while the vocabularies of purpose, morality and meaning remain useful ways of talking about it. He is notably more courteous and more careful than the New Atheist writers, which makes him a harder and more honest interlocutor. ## Principal works - *From Eternity to Here* (2010), on the arrow of time and cosmological entropy. - *The Particle at the End of the Universe* (2012), on the Higgs discovery. - *The Big Picture: On the Origins of Life, Meaning, and the Universe Itself* (2016), the fullest statement of poetic naturalism and the most useful single volume for understanding his position. - *Something Deeply Hidden* (2019), a defence of the Everettian many-worlds interpretation of quantum mechanics. ## His objections to the cosmological arguments **Against the causal premise.** Carroll argues that causation is not a fundamental feature of physics but a useful approximation that emerges at the macroscopic level. Fundamental physics is written in terms of unbroken patterns described by differential equations relating states, not in terms of causes producing effects. On his account, asking for the cause of the universe applies a concept outside the domain where it does work. Engaged at [Causal Principle](/codex/causal-principle/) and [Kalam Cosmological Argument](/codex/kalam-cosmological-argument/). **Against beginning implying a cause.** He grants that classical general relativity predicts a singularity but holds that this marks where the classical theory fails rather than where reality begins, and that quantum-gravitational models permit histories with no first moment. He also argues that a universe with a first moment need not have anything outside it, since the model can simply be a complete description with a boundary. **Against the use of the Borde-Guth-Vilenkin theorem.** Carroll disputes the apologetic deployment of the theorem, arguing that it is a statement about the extendability of classical spacetimes under an averaged expansion condition, not a proof that the universe began to exist, and that it does not apply to quantum-gravitational regimes. See [Borde-Guth-Vilenkin Theorem](/codex/borde-guth-vilenkin-theorem/). Alexander Vilenkin's own correspondence on the point is contested by both sides and is worth reading directly rather than through either camp's summary. **Against fine-tuning.** He argues that the multiverse is a live scientific option motivated independently by inflationary cosmology, that a designer hypothesis makes no sharp predictions, and that on theism one might have expected a universe more hospitable to life than one which is overwhelmingly hostile vacuum. See [Fine-Tuning Argument](/codex/fine-tuning-argument/) and [Multiverse](/codex/multiverse/). **Against entropy-based arguments.** As a specialist on the arrow of time, he holds that the low-entropy past is a genuine puzzle within cosmology rather than evidence for theism. See [Second Law of Thermodynamics](/codex/second-law-of-thermodynamics/) and [Argument from Thermodynamics](/codex/argument-from-thermodynamics/). ## Debate history His 2014 debate with William Lane Craig at the Greer-Heard Forum in New Orleans, on the topic of God and cosmology, is the single most-cited exchange of its kind and is widely regarded, including by some Christian commentators, as a strong performance by Carroll. Reviewing it is close to mandatory before deploying Kalam material against a scientifically literate interlocutor. ## How to engage him - **Do not answer physics with popularisation.** He wrote several of the popularisations. Arguments that rest on a quotable line from a science book will not survive contact. - **Move the dispute to where it belongs.** His core objection to the causal premise is philosophical rather than physical: it assumes that if a concept is not fundamental in the equations, it is not real. That is a metaphysical thesis about emergence and reduction, not a result of physics. See [Metaphysics](/codex/metaphysics/) and [Causal Principle](/codex/causal-principle/). - **Press the contingency form rather than the temporal form.** Arguments from contingency and from sufficient reason do not depend on the universe having a first moment, so his strongest material against Kalam does not reach them. See [Principle of Sufficient Reason](/codex/principle-of-sufficient-reason/) and [Cosmological Arguments](/codex/cosmological-arguments/). - **Concede the BGV point rather than overstating it.** The theorem does not by itself establish an absolute beginning, and claiming it does invites a correction that costs the whole exchange. - **Note where his own view carries commitments.** Many-worlds and the multiverse both multiply unobservable entities on theoretical grounds, which is a reasonable methodology and one that undercuts the demand that theism be rejected for postulating an unobserved entity. ## See also - [Kalam Cosmological Argument](/codex/kalam-cosmological-argument/), the argument he principally targets - [Causal Principle](/codex/causal-principle/), the premise his strongest objection engages - [Borde-Guth-Vilenkin Theorem](/codex/borde-guth-vilenkin-theorem/), the contested apologetic citation - [Fine-Tuning Argument](/codex/fine-tuning-argument/), his second area of objection - [Multiverse](/codex/multiverse/), the alternative he regards as live - [Second Law of Thermodynamics](/codex/second-law-of-thermodynamics/), his specialist field - [Argument from Thermodynamics](/codex/argument-from-thermodynamics/), the argument it bears on - [Cosmological Arguments](/codex/cosmological-arguments/), the family hub - [William Lane Craig](/codex/william-lane-craig/), his principal debate counterpart - [Naturalism](/codex/naturalism/), the framework he defends