No wonder why Giacomo Leopardi’s notebook Zibaldone (1898) is considered to be one of the most important books of the 19th century. Zibaldone is a 2,500 pages (note)book full of wisdom about art, human culture, human nature and society.
The breadth of topics; the depth of understanding; fundamental impressions of things. And it is obviously written straight from the head which gives it a special charm.
For example, at one point Leopardi discusses the nature of fine arts (Zibaldone 8-9). He express his doubt that “people can be judges in our time of works of fine arts.” Two sentences later, when he should elaborate more on it, he writes: “On the first question, if some thought comes to mind, I will write it down later.”
In Zibaldone 14-15, Leopardi tackles the topic of Reason. As it really got me thinking about it, I will put it here in it’s entirety.
Reason is the enemy of all greatness: reason is the enemy of nature: nature is great, reason is small. I mean that it will be more or less difficult for a man to be great the more he is governed by reason, that few can be great (and in art and poetry perhaps no one) unless they are governed by illusions. Thus it happens that those things which we call great (an undertaking, for example) are generally out of the ordinary and consist of a certain disorder. Now, this disorder is condemned by reason. Example: Alexander’s undertaking: all illusion. The extraordinary seems to us to be great. Whether it is actually greater than the ordinary, abstractly speaking, I am not sure: perhaps sometimes it will even measure quite a lot smaller on an abstract scale, and when this strange and famous man is strictly compared with another ordinary and unknown man, he will be found to be the lesser. Nevertheless, because he is extraordinary he is called great: even smallness when it is extraordinary is believed to be, and is called, greatness. Reason does not allow any of this, and we are in the age of reason (if only because the world has aged and is more experienced and colder) and few can now be or are great, especially in the arts. Even someone who is truly great now knows how to weigh and understand his greatness, how to dissect his character in cold blood, examine the merit of his actions, foretell how he may act, write meticulously with acute and detailed reflections about his life. Great enemies, terrible obstacles to greatness: even illusions are now clearly understood as such, and they are fostered with a certain  self-satisfaction, in the full knowledge, however, of what they are. How is it possible, therefore for such illusions, once discovered, to be sufficiently lasting and strong? And for them to inspire us to great things? And, without illusions, what greatness can exist or be hoped for? (An example of when reason is in conflict with nature: a sick man is absolutely incurable and will certainly die in a few days. His relatives, in order to feed him as his illness now requires, suffer real hardship in providing for him; they will sustain losses from doing so even after the sick man’s death, and the sick man will obtain no benefit and may perhaps even be harmed because he will suffer longer. What does naked, dry reason suggest? You are mad if you feed him. What does nature say? You are barbarous and wicked if you do not do everything possible to feed him. It should be noted that religion sides with nature.) It is nature, therefore, that presses great men to great actions. But reason pulls them back: and so reason is the enemy of nature, and nature is great and reason is small. Another proof that reason is often the enemy of nature can be seen in the benefit of toil (as much for health as for everything else), which nature finds repugnant, and, in the same way, in the repugnance of nature to a hundred other things that are either necessary or highly beneficial and therefore encouraged by reason, and vice versa in the inclination of nature toward many other things that are harmful or useless or forbidden, unlawful, and condemned by reason: and with these appetites, nature often tends to harm and destroy itself.