Concepts which have proved useful for ordering things easily assume so great an authority over us, that we forget their terrestrial origin and accept them as unalterable facts. They then become labeled as 'conceptual necessities,' etc. The road of scientific progress is frequently blocked for long periods by such errors.
If I am mistaken in my opinion that the human soul is immortal, I willingly err; nor would I have this pleasant error extorted from me; and if, as some minute philosophers suppose, death should deprive me of my being, I need not fear the raillery of those pretended philosophers when they are no more.
Those wretches who never have experienced the sweets of wisdom and virtue, but spend all their time in revels and debauches, sink downward day after day, and make their whole life one continued series of errors.
If I err in belief that the souls of men are immortal, I gladly err, nor do I wish this error which gives me pleasure to be wrested from me while I live.
There are so many errors and misstatements in that list that I won't even begin to name them. Obama was right about one thing, though - Islam has always been a part of America's story.
Eratosthenes's only tools were sticks, eyes, feet, and brains; plus a zest for experiment. With those tools he correctly deduced the circumference of the Earth, to high precision, with an error of only a few percent. That's pretty good figuring for 2200 years ago.
He soon felt that the fulfillment of his desires gave him only one grain of the mountain of happiness he had expected. This fulfillment showed him the eternal error men make in imagining that their happiness depends on the realization of their desires.