Testing leads to failure, and failure leads to understanding.
In particular I may mention Sophocles the poet, who was once asked in my presence, How do you feel about love, Sophocles? are you still capable of it? to which he replied, Hush! if you please: to my great delight I have escaped from it, and feel as if I had escaped from a frantic and savage master. I thought then, as I do now, that he spoke wisely. For unquestionably old age brings us profound repose and freedom from this and other passions.