Truths ... are too often considered as so true, that they lose all the power of truth, and lie bed-ridden in the dormitory of the soul, side by side with the most despised and exploded errors.
Even the good artisans fell into the same error as the poets; because they were good workmen they thought that they also knew all sorts of high matters, and this defect in them overshadowed their wisdom.
The majority of mankind would seem to be beguiled into error by pleasure, which, not being really a good, yet seems to be so. So that they indiscriminately choose as good whatsoever gives them pleasure, while they avoid all pain alike as evil.
To let them share in the highest offices is to take a risk; inevitably, their unjust standards will cause them to commit injustice, and their lack of judgement will lead them into error. On the other hand there is a risk in not giving them a share, and in their non participation, for when there are many who have no property and no honours they inevitably constitute a huge hostile element in the state. But it can still remain open to them to participate in deliberating and judging.
Indeed the reasoned criticism of a prevailing belief is a service to the proponents of that belief; if they are incapable of defending it, they are well advised to abandon it. This self-questioning and error-correcting aspect of the scientific method is its most striking property.
We cannot see outside what we are not inside. The universe is to us what the huge engine is to the miniature engine; and indication of any error in the tiny engine leads us to imagine trouble in the huge one.