There are various philosophies that have emerged in the past in order to explain the behavior of human beings as well as examine certain trends in the society. In this respect, some of these philosophies are classified under modern thought whereas others fall under the enlightenment age. One of the modern thought includes irrationalism. In reference to Perry et al. (2008), the modern thought of irrationalism differed greatly from the enlightenment thought of human rationality in many ways (p. 678).
To begin with, scholars and researchers from the enlightenment age argued that the society was capable to think rationally. In line with this, human beings were rational and capable of working out evidence based on evidence and proof. However, contrary to the enlightenment philosophies, the modern thought established the fact that human beings were incapable of thinking or behaving rationally. Thus the idea of rationalism was promoted during this period. According to Perry et al. (2008), each individual in the society could arrive at standards of good and evil through rational reflection (p. 189). On the contrary, modern thoughts repudiate the fact that human beings are rational. In arguing against this, Nietzsche argued that man must understand that life, which is replete with cruelty, injustice, uncertainty, and absurdity, is not governed by rational principles (p. 679).
In line with this, the issue of rationality and irrationalism are portrayed in enlightenment age and modern thought respectively. Notably, the issue of morality of good and evil is guided by the rational thinking of human beings. On the contrary, irrationalism concludes that human beings are incapable of thinking rationally and therefore the morality on good and evil cannot be guided by rational thinking. In this, most of the issues or rather ideas and thought that were formulated during the age of enlightenment were repudiated when modern thought and philosophies emerged.