Jowett: absolute truth

And what knowledge ought we to acquire ? May we not answer with absolute truth — A knowledge which will do us good ? EUTHYDEMUS  

And will not knowledge — I mean absolute knowledge — answer to absolute truth ? PARMENIDES  

Str. That we shall some day require this notion of a mean with a view to the demonstration of absolute truth ; meanwhile, the argument that the very existence of the arts must be held to depend on the possibility of measuring more or less, not only with one another, but also with a view to the attainment of the mean, seems to afford a grand support and satisfactory proof of the doctrine which we are maintaining ; for if there are arts, there is a standard of measure, and if there is a standard of measure, there are arts ; but if either is wanting, there is neither. STATESMAN

Ath. Then we are right, and speak the most perfect and absolute truth, when we say that the soul is prior to the body, and that the body is second and comes afterwards, and is born to obey the soul, which is the ruler ? LAWS BOOK X

And are not those who are verily and indeed wanting in the knowledge of the true being of each thing, and who have in their souls no clear pattern, and are unable as with a painter’s eye to look at the absolute truth and to that original to repair, and having perfect vision of the other world to order the laws about beauty, goodness, justice in this, if not already ordered, and to guard and preserve the order of them — are not such persons, I ask, simply blind ? THE REPUBLIC   BOOK VI

Dear Glaucon, I said, you will not be able to follow me here, though I would do my best, and you should behold not an image only, but the absolute truth, according to my notion. Whether what I told you would or would not have been a reality I cannot venture to say ; but you would have seen something like reality ; of that I am confident. THE REPUBLIC BOOK VII

Until the person is able to abstract and define rationally the idea of good, and unless he can run the gauntlet of all objections, and is ready to disprove them, not by appeals to opinion, but to absolute truth, never faltering at any step of the argument — unless he can do all this, you would say that he knows neither the idea of good nor any other good ; he apprehends only a shadow, if anything at all, which is given by opinion, and not by science ; dreaming and slumbering in this life, before he is well awake here, he arrives at the world below, and has his final quietus. THE REPUBLIC BOOK VII