Frank Jackson
1943 CE – Present · Contemporary Era
“There are facts about conscious experience that cannot be captured by any amount of physical information.”
Biography
An Australian analytic philosopher best known for Mary's Room, a widely discussed thought experiment in the philosophy of mind. Jackson's knowledge argument against physicalism generated over a thousand published responses and an entire edited volume. Jackson later recanted his own argument and became a physicalist, making him one of the rare philosophers to publicly reverse a major position.
Major Works
Key Arguments
Click “Philosophy 101” to read the full exploration of each argument.
Mary's Room (The Knowledge Argument)
Jackson asked us to imagine Mary, a brilliant neuroscientist who has spent her entire life in a black-and-white room. Through black-and-white books and monitors, she learns every physical fact about color vision, the wavelengths of light, the neurological processes in the retina and brain, the physics of surfaces. She knows everything physical there is to know about what happens when someone sees red. Then Mary leaves the room and sees a red tomato for the first time. Does she learn something new? It seems obvious that she does, she learns what it is like to see red. But if she already knew all the physical facts and still learned something new, then the physical facts cannot be all the facts. There must be non-physical facts about conscious experience, qualia, that physicalism leaves out.
Why it matters: A highly influential argument in late 20th-century philosophy of mind. The thought experiment crystallizes the 'hard problem of consciousness': why do physical processes give rise to subjective experience at all? Jackson later reversed his position, arguing that Mary's surprise upon seeing red does not actually prove physicalism false, a recantation that itself became philosophically significant, demonstrating that even the strongest intuitions about consciousness may mislead us.
The Recantation: From Qualia to Physicalism
Jackson came to reject his own famous argument. His reasoning turned on the causal efficacy of qualia: when Mary sees red for the first time and says 'Wow!', her conscious experience must have caused that utterance. But if qualia cause physical events (speech, behavior), they must be part of the physical causal order, which contradicts the epiphenomenalism his original argument seemed to support. Jackson concluded that physicalism provides the better explanation after all, and that the powerful intuition behind Mary's Room, compelling as it feels, is ultimately misleading.
Why it matters: Jackson's willingness to publicly abandon his most famous argument demonstrated intellectual honesty rare in philosophy. The recantation also sharpened the debate: if even the argument's inventor was not ultimately convinced, the challenge of explaining consciousness within physicalism becomes a matter of accounting for why the intuition is so compelling rather than accepting it at face value.
Conceptual Analysis and the Canberra Plan
Jackson argued that conceptual analysis, the careful examination of what our concepts mean and how they connect to each other, remains central to philosophy and is not made obsolete by empirical science. His approach, known as the Canberra Plan (developed with colleagues at the Australian National University), holds that philosophical questions often ask how our folk concepts (like 'belief', 'causation', 'free will') relate to the world described by science. The task is to identify which natural properties, if any, play the roles specified by our concepts.
Why it matters: Provided a rigorous defense of philosophy's distinctive method at a time when some argued that science alone could answer philosophical questions. The Canberra Plan influenced metaphysics, philosophy of mind, and meta-ethics, offering a systematic framework for how philosophical and scientific inquiry relate.
Lasting Influence
Created Mary's Room, a widely discussed thought experiment in philosophy of mind, and made significant contributions to meta-ethics and the philosophy of consciousness.
Your Reading Path
The Companion Guide
Seven eras of philosophy in one volume — reading lists, key terms, journal prompts · $19.99