Giacomo Leopardi (1798-1837) was a great Italian poet. He was also one of Western civilization’s great pessimists. Below is an 1821 extract from his Zibaldone di pensieri (“Commonplace Book of Thoughts”):

The power of nature and the weakness of reason. I’ve said elsewhere that for opinions to have a real influence on people, they must take the form of passions…. One could quote endless examples to demonstrate this point. But since all opinions that aren’t, or don’t seem to be, prejudices will have only pure reason to support them, in the ordinary way of things they are completely powerless to influence people.

Religious folks (even today, and maybe more these days than ever before, in reaction to the opposition they meet) are more passionate about their religion than their other passions (to which religion is hostile); they sincerely hate people who are not religious (though they pretend not to) and would make any sacrifice to see their system triumph (actually they already do this, mortifying inclinations that are natural and contrary to religion), and they feel intense anger whenever religion is humbled or contested.

Non-religious people, on the other hand, so long as their not being religious is simply the result of a cool-headed conviction, or of doubt, don’t hate religious people and wouldn’t make sacrifices for their unbelief, etc., etc. So it is that hatred over matters of opinion is never reciprocal, except in those cases where for both sides the opinion is a prejudice, or takes that form.

There’s no war then between prejudice and reason, but only between prejudice and prejudice, or rather, only prejudice has the will to fight, not reason. The wars, hostilities and hatreds over opinions, so frequent in ancient times, right up to the present day, in fact, wars both public and private, between parties, sects, schools, orders, nations, individuals—wars which naturally made people determined enemies of anyone who held an opinion different from their own—only happened because pure reason never found any place in their opinions, they were all just prejudices, or took that form, and hence were really passions.

Poor philosophy then, that people talk so much about and place so much trust in these days. She can be sure no-one will fight for her, though her enemies will fight her with ever greater determination; and the less philosophy influences the world and reality, the greater her progress will be, I mean the more she purifies herself and distances herself from prejudice and passion. So never hope anything from philosophy or the reasonableness of this century.

About 100 years later, William Butler Yeats (1865-1939) expressed a similar thought in The Second Coming:

Turning and turning in the widening gyre
The falcon cannot hear the falconer;
Things fall apart; the centre cannot hold;
Mere anarchy is loosed upon the world,
The blood-dimmed tide is loosed, and everywhere
The ceremony of innocence is drowned;
The best lack all conviction, while the worst
Are full of passionate intensity.

In the 21st century, nobody believes in pure reason anymore. The question now is whether the more reasonable have enough passion to counteract the less reasonable. Leopardi would have been doubtful.

Note: the Leopardi quote is from a New York Review of Books blog post that is much less interesting: http://www.nybooks.com/blogs/nyrblog/2013/oct/17/headline-headaches/