Famous personalities on Islam & Muhammad

Muslims frequently like to quote positive comments about Islam and Muhammad said by famous people. Now let us read some quotes which muslims avoid.

Voltaire - one of the greatest philosophers of all time says this in his play Le fanatisme, ou Mahomet le Prophete [The complete works of Voltaire, Volume 20, Part 2 (rough translation)]

But that a camel trader causes a tumult in his little hole; that he associates with some of his unfortunate neighbors and wants to make them believe that he was talking to the archangel Gabriel; that he brags to have been carried away to heaven where he received a part of that indigestible book which makes the common sense shudder at every page; that, in order to make that book respected, he carries iron and fire all over his country; that he strangled the fathers, abducts the daughters and leaves to the vanquished only the choice between death and his faith, this is certainly something, that no human can excuse, unless he has been born as a Turk and superstition has smothered every natural light inside of him.

Alexis-Charles-Henri Clérel de Tocqueville - the french political thinker and historian said in his book The Tocqueville reader: a life in letters and politics (Page 229)

I studied the Koran a great deal. I came away from that study with the conviction that by and large there have been few religions in the world as deadly to men as that of Muhammad. As far as I can see, it is the principal cause of the decadence so visible today in the Muslim world and, though less absurd than the polytheism of old, its social and political tendencies are in my opinion more to be feared, and I therefore regard it as a form of decadence rather than a form of progress in relation to paganism itself.

David Hume, the eminent Scottish historian and philosopher, in his book, Essays and Treatises on Several Subjects: Essays, moral, political [Page 226] said:

The admirers and followers of the Alcoran insist on the excellent moral precepts interspersed through that wild and absurd performance. But it is to be supposed, that the Arabic words, which correspond to the English, equity, justice, temperance, meekness, charity were such as, from the constant use of that tongue, must always be taken in a good sense; and it would have argued the greatest ignorance, not of morals, but of language, to have mentioned them with any epithets, besides those of applause and approbation. But would we know, whether the pretended prophet had really attained a just sentiment of morals?

Let us attend to his narration; and we shall soon find, that he bestows praise on such instances of treachery, inhumanity, cruelty, revenge, bigotry, as are utterly incompatible with civilized society. No steady rule of right seems there to be attended to; and every action is blamed or praised, so far only as it is beneficial or hurtful to the true believers.

Scottish essayist and historian Thomas Carlyle (Taken from Page 45 "Islam the basics" by Colin turner) said,

A wearisome confused jumble...endless iterations, long-windedness, entanglement; most crude, incondite-insupportable stupidity, in short.

The entire point of this post is to present the appeal to authority fallacy. The very purpose of the presentation of these quotations is to show that many people with anti-islamic opinions can also be quoted thus such (pro-islamic) quotes have no value in determining the authenticity of Islam. Instead, we must refer to evidence and arguments rather than people's opinion and authority.