Once more, success in the other arts presupposes a diet as abstemious as any invalid’s; eat and drink to your heart’s content, and you make no progress in your studies.

 Other arts, again, are useless to their professor unless he has his plant; you cannot play the flute if you have not one to play; lyrical music requires a lyre, horsemanship a horse. But of ours one of the excellences and conveniences is that no instrument is required for its exercise.

 

 Other arts we pay, this we are paid, to learn.

 Further, while the rest have their teachers, no one teaches sponging; it is a gift from Heaven, as Socrates said of poetry.

 Then do not forget that, while the others have to be suspended during a journey or a voyage, this may be in full swing under those circumstances too.