“For my part, Brutus, I am perfectly persuaded that it is expedient for me to philosophize; for what can I do better, especially as I have no regular occupation? But I am not for limiting my philosophy to a few subjects; for philosophy is a matter in which it is difficult to acquire a little knowledge without acquainting yourself with many, or all its branches.
Philosophy would never have been in such esteem in Greece itself, if it had not been for the strength which it acquired from the contentions and disputations of the most learned men; and therefore I recommend all men who have abilities to follow my advice to snatch this art also from declining Greece, and to transport it to this city.
Let philosophy, then, derive its birth in Latin language from this time, and let us lend it our assistance, and bear patiently to be contradicted and refuted; and although those men may dislike such treatment who are bound and devoted to certain predetermined opinions, and are under such obligations to maintain them that they are forced, for the sake of consistency, to adhere to them even though they do not themselves wholly approve of them; we, on the other hand, who pursue only probabilities, and who cannot go beyond that which seems really likely, can confute others without obstinacy, and are prepared to be confuted ourselves without resentment.”
(Tusculan Disputations, II.1-2)
Cicero on the value of philosophy