Frank Jackson: Mary's Room & Philosophy

Biography

Frank Cameron Jackson was born in 1943 in Melbourne, Australia, into a family of philosophers: both his parents, Reginald and Elizabeth Jackson, taught philosophy. He studied at the University of Melbourne and then at Oxford University, where he earned his doctorate. Jackson spent most of his career at Monash University in Melbourne, where he became a professor of philosophy and where he wrote the work for which he is best known. In 2007 he moved to Princeton University's Center for Human Values, and he later returned to Australia, where he was appointed distinguished professor at the Australian National University. Jackson has worked across philosophy of mind, metaphysics, ethics, and philosophy of religion, and he is a fellow of the Australian Academy of the Humanities.

Historical Background

Jackson's most famous contribution appeared in the 1980s, at the height of the debate over physicalism — the view that everything, including the mind, is physical. By that decade, the identity theory and functionalism had become the dominant physicalist positions, and many philosophers believed that the explanatory gap identified by Thomas Nagel in 1974 could be closed by better science or better concepts. Jackson's 1982 paper "Epiphenomenal Qualia" introduced a thought experiment designed to show that the physicalist program leaves something out: the phenomenal character of experience, or qualia.

The thought experiment concerns Mary, a brilliant neuroscientist who has lived her entire life in a black-and-white room, seeing only black, white, and shades of gray. Mary has learned everything there is to know about the physical facts of color vision — the wavelengths of light, the structure of the retina, the neural processing in the visual cortex. She knows all the physical facts about how human beings perceive color. The question Jackson poses is this: when Mary first leaves the room and sees a red rose, does she learn something new? Does she learn what it is like to see red?

Core Ideas

The Knowledge Argument

Jackson's answer is yes: Mary learns something new. She acquires new knowledge — knowledge of what the experience of red is like. But if she already knew all the physical facts, and she still learns something new, then the new knowledge cannot be knowledge of a physical fact. It must be knowledge of a non-physical fact: a fact about what it is like to see red, a fact about the phenomenal character of experience. This is the knowledge argument, and it is directed squarely against physicalism. If physicalism were true — if all facts were physical facts — then knowing all the physical facts would suffice for knowing all the facts, and Mary would learn nothing upon leaving her room. Since she does learn something, physicalism must be false.

The argument is closely related to Nagel's argument about the bat. Nagel argued that objective physical knowledge leaves out the subjective character of experience; Jackson sharpened this into a formal argument against physicalism. The knowledge argument has been called the most powerful argument against physicalism in contemporary philosophy, and it has generated an enormous literature of responses.

Qualia and Phenomenal Information

The knowledge argument rests on the notion of qualia — the intrinsic, subjective qualities of experience: the redness of red, the painfulness of pain, the sweetness of sugar. Jackson argued that qualia are real features of the world and that the information they provide — phenomenal information — cannot be captured in physical terms. Physicalists responded in several ways. Some argued that Mary does not gain new propositional knowledge but only new abilities — the ability to recognize, imagine, and remember colors (the "ability hypothesis" defended by Daniel Dennett and others). Others argued that Mary's new knowledge is just old knowledge under a new mode of presentation (the "new knowledge, old fact" response). Jackson's argument set the agenda for this debate, and each response continues to be refined today.

Epiphenomenalism

In his 1982 paper, Jackson drew a striking conclusion from the knowledge argument: if qualia are real but cannot be reduced to physical facts, and if the physical world is causally closed (every physical event has a sufficient physical cause), then qualia must be causally inert — epiphenomena. On this view, conscious experience is a by-product of brain processes but does not itself cause anything: the feeling of pain accompanies the neural events that cause pain behavior, but the feeling itself does no causal work. Epiphenomenalism preserves the reality of qualia while respecting the causal closure of physics, but it has seemed deeply counterintuitive to many: if qualia cause nothing, why would evolution have produced them?

Jackson himself later came to doubt epiphenomenalism. In a series of papers in the 1990s and in his 1998 book From Metaphysics to Ethics, he conceded that the knowledge argument is compatible with physicalism if we allow that "physical" information can be understood broadly enough, and he abandoned epiphenomenalism in favor of a form of physicalism. His change of mind is itself a famous episode in the recent history of the philosophy of mind, and commentators disagree about whether his later position successfully answers his earlier argument.

Major Works

Perception: A Representative Theory (1977) developed Jackson's early view that perception involves sense data. "Epiphenomenal Qualia" (1982) and "What Mary Didn't Know" (1986) contain the knowledge argument. His work on conditionals, including the papers later collected in his logical writings, and From Metaphysics to Ethics: A Defence of Conceptual Analysis (1998) present his later, physicalist-friendly framework, in which he defends the role of conceptual analysis and a "two-dimensional" approach to the mind-world relation.

Philosophical Influence

The knowledge argument is one of the most debated arguments in contemporary philosophy. It forced physicalists to explain exactly what Mary gains on leaving her room, and the resulting literature — on phenomenal concepts, ability knowledge, modes of presentation, and the metaphysics of color — constitutes a major research program in its own right. The argument also reinforced the centrality of qualia to the science of consciousness: any complete theory of consciousness must account for the phenomenal character that the Mary case highlights. Jackson's thought experiment is now a standard entry point for students and a permanent fixture of the debate between physicalists and their critics, alongside the philosophical zombie argument of David Chalmers.

Jackson's later defense of conceptual analysis influenced metaphysics and metaethics, and his career illustrates the productive instability of the physicalism debate: the man who gave physicalism its most famous counterexample spent the second half of his career arguing that physicalism can be reconciled with the argument's lessons.

Related Concepts

The knowledge argument connects directly to the central problems of the philosophy of mind. It is the canonical statement of the case for qualia and a close cousin of the explanatory gap and of Nagel's bat argument. Its conclusion bears on the hard problem of consciousness, on panpsychism, and on the debate between dualism and materialism. For understanding why many philosophers still doubt that physics can explain the felt character of experience, Mary's Room remains the clearest and most powerful starting point.