William Kingdon Clifford

1845-1879 · English · Epistemology of belief, philosophy of science, geometry

It is wrong always, everywhere, and for anyone, to believe anything upon insufficient evidence.

He was Second Wrangler at Cambridge, a professor of mathematics at University College London at twenty-six, and dead of tuberculosis at thirty-three. In between he did the geometry that carries his name, gave a paper in 1870 suggesting that matter might be nothing but variation in the curvature of space and that this curvature might propagate in waves — a suggestion nobody could make anything of for forty-five years, until Einstein — and wrote a nine-page essay that has been argued about ever since.

Topics William Kingdon Clifford addresses

• the ethics of belief
• the shipowner
• insufficient evidence
• credulity
• the duty of inquiry
• evidentialism
• the weight of authority
• the limits of inference
• mind-stuff
• the elementary feeling
• consciousness as a compound
• the objective and the subjective order
• space-theory of matter
• the curvature of space
• non-Euclidean geometry
• Clifford algebras
• biquaternions
• the scientific basis of morals
• the tribal self
• conscience as social
• right and wrong
• the postulates of the science of space

Questions to put to William Kingdon Clifford

The Ethics of Belief and the Duty of Inquiry

• What did you mean by 'it is wrong always, everywhere, and for anyone, to believe anything upon insufficient evidence'?
• Why is the shipowner guilty even though he sincerely believed the ship was safe?
• How is my believing something on weak evidence a danger to other people?
• When am I allowed to rely on what someone else tells me?
• What evidence do you have for the principle that we need sufficient evidence?
• How much evidence is enough to make a belief permissible?

Religion, Credulity, and the Community

• Does your argument single out religious belief for special criticism?
• Why can't I believe in God if the belief makes me a better person?
• How does one person's credulity weaken the habits of inquiry in everyone else?
• What's wrong with believing something dear to me if I'm not hurting anyone?
• Can religious testimony ever count as sufficient evidence?

Mind-Stuff and the Nature of Consciousness

• What do you mean by mind-stuff?
• How can consciousness be built out of elementary feelings?
• If matter is really mind-stuff in disguise, why does it seem so different from thought?
• What's the difference between the objective order and the subjective order?
• Does your view mean everything is conscious, even rocks?

The Space-Theory of Matter and Curved Space

• What did you mean by saying matter is really the curvature of space?
• How can space be curved if it seems flat to us?
• Why did you think the motion of matter is actually a wave in the curvature of space?
• Were you proposing a real physical theory or just a mathematical speculation?
• What would it take to test whether matter is curved space?

Morals, Conscience, and the Tribal Self

• What is the tribal self and how does it shape my conscience?
• If moral rules come from the needs of the community, are they just arbitrary customs?
• How do you ground morality in science without making it relative?
• What's the difference between right and wrong on your view?
• Can there be moral progress if morality is rooted in the tribe?

Converse with William Kingdon Clifford on Simposeum. Replies are grounded in William Kingdon Clifford's own writing, cited to the page.