Though a lesser known figure outside Italy, Giacomo Leopardi was highly influential in the 19th century, especially for Schopenhauer and Nietzsche.  In Leopardi's darkly comic essays, aphorisms, fables and parables, life is often described as a sort of divine joke or mistake. According to Leopardi, because of our conscious sense of time and our endless search for truth, the human desire for happiness can never be truly satiated and joy cannot last. Leopardi claims that "Therefore they greatly deceive themselves, [those] who declare and preach that the perfection of man consists in knowledge of the truth and that all his woes proceed from false opinions and ignorance, and that the human race will at last be happy, when all or most people come to know the truth, and solely on the grounds of that arrange and govern their lives."  Furthermore, Leopardi believes that for man it is not possible to forget truth and that "it is easier to rid oneself of any habit before that of philosophizing."
The second volume consisted of several essays expanding topics covered in the first. Most important are his reflections on death and his theory on sexuality , which saw it as a manifestation of the whole will making sure that it will live on and depriving humans of their reason and sanity in their longing for their loved ones. Less successful is his theory of genetics : he argued that humans inherit their will, and thus their character, from their fathers, but their intellect from their mothers and he provides examples from biographies of great figures to illustrate this theory.  The second volume also contains attacks on contemporary philosophers such as Fichte , Schelling , and Hegel .