... he stood on the flat road to heaven and buttered slides to hell for all the rest.

Oliver Wendell Holmes (1841-1935) on George Santayana (1863-1952), American philosopher

... one of the most depraved, vicious and revolting humbugs who ever escaped from a nightmare or a lunatic asylum.

Preston Sturges on Aleister Crowley (1875-1947)

A liar and a father of lies.

Dante (1265-1321) on the Devil

A philosophizing serpent.

Horace Walpole (1717-97), letterist and memoirist, on Mary Wollstonecraft (1759-97), British feminist

Actually I always loathed the Viennese quack. I used to stalk him down dark alleys of thought, and now we shall never forget the sight of old, flustered Freud seeking to unlock his door with the point of his umbrella.

Vladimir Nabokov (1899-1977) on Sigmund Freud (1856-1939)

Against Locke's philosophy I think it an unanswerable objection that, although he carried his throat about with him in this world for seventy-two years, no man ever condescended to cut it.

Thomas de Quincey (1785-1859), British writer, in 'On Murder Considered As One of the Fine Arts' (1827), on John Locke (1632-1704): English philosopher

Con philosophers, analysts, God and the devil* I must believe in the Apostolic Succession, there being no other way of accounting for the descent of the Bishop of Exeter from Judas Iscariot.

Revd Sydney Smith (1771-1845) on the Bishop of Exeter

Hume's philosophy, whether true or false, represents the bankruptcy of eighteenth-century reasonableness.

Bertrand Russell (1872-1970) on David Hume (1711-76), Scottish philosopher

I have no patience whatever with these Gorilla damnifications of humanity.

Thomas Carlyle (1795-1881) on Charles Darwin (1809-82)

Luther was the foulest of monsters.

Pope Gregory XV on Martin Luther (1483-1546)

Maybe it would have been better if neither of us had been born.

Napoleon Bonaparte (1769-1821) on Jean-Jacques Rousseau (1712-78)

My prayer to God is a very short one: 'Oh, Lord, make my enemies ridiculous.' God has granted it.

Voltaire (1694-1778)

Plato is a bore.

Friedrich Wilhelm Nietzsche (1844-1900)

She is an infidel... a vulgar and foolish one.

John Ruskin (1819-1900), art critic and author, on Harriet Martineau (1802-76), British feminist and writer

Smug Sydney.

Lord Byron (1788-1824) on the Revd Sydney Smith

Susan is lean, cadaverous and intellectual, with the proportions of a file and the voice of a hurdy-gurdy.

Anonymous writer in the New York World (1866) on Susan Bronwell Anthony (1820-1906), American feminist

The arch-philistine Jeremy Bentham was the insipid, pedantic, leather-tongued oracle of the bourgeois intelligence of the nineteenth century.

Karl Marx (1818-83) on Jeremy Bentham (1748-1832), British political philospher

The bear loves licks and forms her young, but bears are not philosophers.

Edmund Burke (1729-97) on Jean-Jacques Rousseau (1712-78)

The Lord strike him with madness and blindness. May the heavens empty upon him thunderbolts and the wrath of the Omnipotent burn itself unto him in the present and future world. May the Universe light against him and the earth open to swallow him up.

Pope Clement VI (1478-1534) on a now anonymous subject

The next time anyone asks you 'What is Bertrand Russell's Philosophy?' the correct answer is 'What year please?'

Sydney Hook on Bertrand Russell

The Puritan hated bear-baiting, not because it gave pain to the bear, but because it gave pleasure to the spectators.

Thomas Babington Macaulay (1800-59), History of England

The truth is that Sydney Smith is naturally coarse, and a lover of scurrilous language.

John Ward, Earl of Dudley (1781-1833) on Revd Sydney Smith

Voltaire, or the anti-poet - the king of nincompoops, the prince of the superficial, the anti-artist, the spokesman of janitresses.

Charles Baudelaire (1821-67) on Voltaire (1694-1778)

What a hideous, odd-looking man Sydney Smith is! With a mouth like an oyster, and three double chins.

Mrs Brookfield on the Revd Sydney Smith (1771-1845)