Monster! I said; you have been carrying me round in a circle, and all this time hiding from me the fact that the life according to knowledge is not that which makes men act rightly and be happy, not even if knowledge include all the sciences, but one science only, that of good and evil. For, let me ask you, Critias, whether, if you take away this, medicine will not equally give health, and shoemaking equally produce shoes, and the art of the weaver clothes?--whether the art of the pilot will not equally save our lives at sea, and the art of the general in war? Quite so. And yet, my dear Critias, none of these things will be well or beneficially done, if the science of the good be wanting. True. But that science is not wisdom or temperance, but a science of human advantage; not a science of other sciences, or of ignorance, but of good and evil: and if this be of use, then wisdom or temperance will not be of use. And why, he replied, will not wisdom be of use? For, however much we assume that wisdom is a science of sciences, and has a sway over other sciences, surely she will have this particular science of the good under her control, and in this way will benefit us. And will wisdom give health? I said; is not this rather the effect of medicine? Or does wisdom do the work of any of the other arts,--do they not each of them do their own work? Have we not long ago asseverated that wisdom is only the knowledge of knowledge and of ignorance, and of nothing else? That is obvious. Then wisdom will not be the producer of health. Certainly not. The art of health is different. Yes, different. Nor does wisdom give advantage, my good friend; for that again we have just now been attributing to another art. Very true. How then can wisdom be advantageous, when giving no advantage? That, Socrates, is certainly inconceivable.