Everything desires not like but unlike: for example, the dry desires the moist, the cold the hot, the bitter the sweet, the sharp the blunt, the void the full, the full the void, and so of all other things; for the opposite is the food of the opposite, whereas like receives like receives nothing from like.
Then may we not fairly plead in reply that our true lover of knowledge naturally strives for truth, and is not content with common opinion, but soars with undimmed and unwearied passion till he grasps the essential nature of things with the mental faculty fitted to do so, that is, with the faculty which is akin to reality, and which approaches and unites with it, and begets intelligence and truth as children, and is only released from travail when it has thus reached knowledge and true life and satisfaction?
The cure of the part should not be attempted without treatment of the whole. No attempt should be made to cure the body without the soul. Let no one persuade you to cure the head until he has first given you his soul to be cured, for this is the great error of our day, that physicians first separate the soul from the body.
Between knowledge of what really exists and ignorance of what does not exist lies the domain of opinion. It is more obscure than knowledge, but clearer than ignorance.
What the expression is intended to mean, I think, is that there is a better and a worse element in the character of each individual, and that when the naturally better element controls the worse then the man is said to be "master of himself", as a term of praise. But when - as a result of bad upbringing or bad company one s better element is overpowered by the numerical superiority of one s worse impulses, then one is criticized for not being master of oneself and for lack of self control.
Education is the constraining and directing of youth towards that right reason, which the law affirms, and which the experience of the best of our elders has agreed to be truly right.