Etymology: Every Man at Forty is a Fool or His Own Physician

“It is proverbial that every man at forty is a fool or his own physician; yet we do not consider Ethics to include the art of medicine”

Henry Sidgwick, The Methods of Ethics (1874)

i.e. every sensible man should have learned to take care of himself by the age of forty. Perhaps this was more true in Sidgwick’s time; nowadays, even fools can live to forty and beyond.

Quotations

Cassell’s Book of Quotations Proverbs and Household Words (1914) gives two citations:

I have heard that Tiberius used to say that that man was ridiculous who, after sixty years, appealed to a physician.

Plutarch De Sanitate Tuenda Vol 2.

[Tiberius] was wont to mock at the arts of physicians, and at those who, after thirty years of age, needed counsel as to what was good or bad for their bodies.”

Tacitus Annals Book 6, chap 46

Presented below in context:

I have heard that Tiberius Caesar was wont to say, that he was a ridiculous man that held forth his hand to a physician after sixty. But it seems to me to be a little too severely said. But this is certain, that every man ought to have skill in his own pulse, for it is very different in every man; neither ought he to be ignorant of the temper of his own body, as to heat and cold, or what things do him good, and what hurt.

Plutarch De Tuenda Sanitate Praecepta W.W.Goodwin trans. (1873) sec. 26 Perseus

But even while his strength was fast failing he gave up none of his debaucheries. In his sufferings he would simulate health, and was wont to jest at the arts of the physician and at all who, after the age of thirty, require another man’s advice to distinguish between what is beneficial or hurtful to their constitutions.

Tacitus Annals Book 6, chap 46 Perseus

Cassell corroborates this account with a quotation of Suctonius (which I was unable to cross reference) that

From the age of thirty, [Tiberius] ruled himself according to his own judgment wihtout the help or advice of the physicians.

Suctonius Tiberius chap. 68