Once upon a time children's readers contained chapters describing the weaknesses of famous people. That Voltaire's character left much to be desired is evident from the following lesson read by school children more than a century and a half ago.
He loves the court, yet grows weary of it: he has sensibility without connections, and is voluptuous without passion. He is attached to nothing by choice, but to every thing through inconstancy. As he reasons without principle, his judgment has its intervals, like the folly of others. He has a clear head, but a corrupt heart. He thinks of every thing, and treats every thing with derision.
He is a libertine, without a constitution for pleasure; and can moralize without morality. His vanity is excessive, but his avarice still greater; he therefore writes less for fame than money, for which he may be said both to hunger and thirst. He is in haste to work, that he may haste to live: lie was made to enjoy, and determined only to hoard. Such is the man, and such is the author.
Voltaire has much foreign and much French literatune; nor is he deficient in that sort of mixed erudition that is now so fashionable. He is a politician, a naturalist, a geometrician, or whatever he pleases; but he is always superficial, because he is not able to think deeply. He could not, however, flourish as he does upon those subjects, without great ingenuity.
His taste is rather delicate than just; he is a witty satirist, a bad critic, and a dabbler in the abstracted sciences: imagination is his element, and yet strange as it is, he has no invention.