And that thou mightest learn, that not by addition but by taking away this evil is stayed; if thou hadst ever had an absurd desire to fly and to be borne through the air, how wouldest thou extinguish this unreasonable desire? By fashioning wings, and preparing other instruments, or by convincing the mind that it is desiring things impossible, and that one should attempt none of these things? It is quite plain, that by convincing the mind. But that, thou mayest say, is impossible. But this again is more impossible, to find a limit for this desire. For indeed it is more easy for men to fly, than to make this lust cease by an addition of more. For when the objects of desire are possible, one may be soothed by the enjoyment of them, but when they are impossible, one must labor for one thing, to draw ourselves off from the desire, as otherwise at least it is not possible to recover the soul.