Daily question, August 16, 2026
Politics
The only purpose for which power can be rightfully exercised over any member of a civilised community, against his will, is to prevent harm to others.
Source: John Stuart Mill, On Liberty
The harm principle draws a line around private conduct the state is not entitled to cross.
Mathematics
Probability theory is nothing but common sense reduced to calculation.
Source: Pierre-Simon Laplace, Essai philosophique sur les probabilites
Laplace treated probability as a measure of human ignorance about a determined world, not a feature of the world itself.
Physics
Hypotheses non fingo: I frame no hypotheses.
Source: Isaac Newton, General Scholium, Principia, 2nd edition, 1713
Newton refused to speculate on what gravity is, only on how it behaves; its cause stayed an open question for centuries.
Psychology
All the world is not, of course, a stage, but the crucial ways in which it isn't are not easy to specify.
Source: Erving Goffman, The Presentation of Self in Everyday Life
Goffman's theater metaphor for social life is famous, but he hedged it himself; the hedge is the harder, more honest claim.
Philosophy
Reason is, and ought only to be the slave of the passions.
Source: Hume, A Treatise of Human Nature
Hume denied that reason alone could ever move you to act. Wanting has to come first; reason only finds the means.
Biology
In nature nothing exists alone.
Source: Rachel Carson, Silent Spring
A short line backing her larger argument that pesticides do not stay contained to their target; they move through food chains and water.
