Idonot know whether itoughttobe so, butcertainlysilly things do cease to be silly if theyare done by sensible people in an impudent way.Wickedness is always wickedness, but folly is not always folly. It depends upon the character of those who handle it.

-Austen,Jane
  Emma, ch.26.

Goldsmith tells us, when a lovely woman stoops to folly, shehasnothing to do but die; and when shestoopsto be disagreeable, it is equally to be recommended as a clearer of ill-fame. See Goldsmith 361:47.

-Austen,Jane
  Emma, ch.45.

It is often seen that bad husbands have very good wives; whether it be that it raiseth the price of their husband's kindness when it comes, or that the wives take a pride in their patience. But this never fails, if the bad husbands were of their own choosing, against their friends' consent; for then they will be sure to make good their own folly.

-Bacon, Francis,Viscount St Albans
  Essays, no.8,'Of Marriage and the Single Life'.

As a dog returneth to his vomit, so a fool returneth to his folly.

-Bible (Old Testament)
Proverbs 26:11.

Dead flies causethe ointment of theapothecary tosend forth a stinking savour: so doth a little folly him that is in reputation for wisdom and honour.

-Bible (Old Testament)
Ecclesiastes10:1.

O ye wha are sae guid yoursel, Sae pious and sae holy, Ye've nought to do but mark and tell Your Neebours'fauts an folly!

-Burns, Robert
  'Address to the Unco Guid, or the Rigidly Righteous', stanza1.

All my joys to this are folly, Naught so sweet as melancholy.

-Burton, Robert pseudonym DemocritusJunior
Anatomy of Melancholy,'The  Author's  Abstract of Melancholy'.

Fashionöa word which knaves and fools may use, Their knavery and folly to excuse.

-Churchill, Charles
The Rosciad, l.455^6.

Fashion, though Folly's child, and guide of fools, Rules e'en the wisest, and in learning rules.

-Crabbe, George
The Library (published1808), l.167^8.

Such is our pride, our folly, or our fate, That few, but such as cannot write, translate.

-Denham, SirJohn
  'To Richard Fanshaw'.

Do not let me hear Of the wisdom of old men, but rather of their folly.

-Eliot,T(homas) S(tearns)
  Four Quartets,'East Coker', pt.2.

There are as many fools at a university as anywhere† But their folly,I admit, has a certain stampöthe stamp of university training, if you like. It is trained folly.

-Gerhardie,William Alexander
  Polyglots, ch.7.

When lovely woman stoops to folly And finds too late that men betray, What charm can soothe her melancholy, What art can wash her guilt away?

-Goldsmith, Oliver
  The Vicar of  Wakefield, ch.29.

To each his suff'rings, all are men, Condemned alike to groan; The tender for another's pain, Th'unfeeling for his own. Yet ah! why should they know their fate? Since sorrow never comes too late, And happiness too swiftly flies. Thought would destroy their paradise. No more; where ignorance is bliss, 'Tis folly to be wise.

-Gray,Thomas
  Ode on a Distant Prospect of Eton College (published1747), l.91^100.

And on that grave where English oak and holly And laurel wreaths entwine, Deem it not all a too presumptuous folly, This spray of Western pine!

-Harte, (Francis) Bret
  On the death of Charles Dickens.'Dickens in Camp', stanza10.

Historians spend their lives and lavish ink Explaining how great commonwealths collapse From great defects of policyöperhaps The cause is sometimes simpler than they think. † Have more states perished, then, For having shackled the enquiring mind, Than those who, in their folly not less blind, Trusted the servile womb to breed free men?

-Hope, A(lec) D(erwent)
  'Advice toYoung Ladies', in Collected Poems1930^1970 (1972).

Only man behaves with such gratuitous folly. It is the price he has to pay for being intelligent but not, as yet, quite intelligent enough.

-Huxley, Aldous Leonard
  Texts and Pretexts,'Amor Fati'.

A man hates to be moved to folly bya noise.

-Arabia
  Of the emotion arousedby the military trumpets. TheMint, pt.3, ch.9.

The root of Evil, Avarice That damn'd ill-natur'd, baneful Vice, Was Slave to Prodigality, That noble Sin; whilst Luxury Employed a Million of the Poor, And odious Pride a Million more; Envy itself, and Vanity, Were Ministers of Industry; Their darling Folly, Fickleness, In Diet, Furniture and Dress That strange ridic'lous Vice, was made That very Wheel that turned theTrade.

-Mandeville, Bernard
  The Fable of the Bees, or, Private Vices, Publick Benefits (2nd edn.).

Hence vain deluding Joys, The brood of Folly without father bred, How little you bestead, Or fill the fixe'  d mind with all your toys; Dwell in some idle brain, And fancies fond with gaudy shapes possess, As thick and numberless As the gay motes that people the sunbeams.

-Milton,John
c.1631 Il Penseroso, opening lines.