Introduction Today, I will think of the differences between objectivism and subjectivism. I will not review their philosophical foundation. Instead, I will speak of the role of subjectivism and objectivism in understanding reality – argue that objectivism (science), not subjectivism (existential perspectivism), is the best way to know truth about the world. To make my argument, I will estimate the following statement from the perspectives of different epistemologies: cancer is a critical health condition. Choosing an example for consideration My argument is based on the belief that science, not personal experience, is the best way to know truth about reality because it is empirical evidence that is a more comprehensive and reliable source of knowledge compared to individual’s experience or perception of the world. Understanding Locke’s stance I will prove my argument by contradiction between two opinions. John Locke claims that “all ideas come from sensation or reflection” (Locke). He believes that the foundation of knowledge is personal experience. In his view, it is true for both external subjects and internal operations. In this way, there are two ways for obtaining knowledge. The first one is the operation of a human mind and senses. It is connected to understanding external developments and phenomena, such as ideas of “yellow, white, heat, cold, soft, hard, bitter, sweet, and all those which we call sensible qualities” (Locke). This process is known as sensation. Another way is reflection. It is associated with one’s soul and the processes of thinking, reasoning, questioning, and other similar activities. According to Locke, the combination of the two is the foundation for understanding the main ideas about reality. Reviewing the position of Nietzsche On the other hand, Friedrich Nietzsche states that even though knowledge may come from sensation and experience and “all our categories of reason are of sensual origin, [they are] derived from the empirical world” (Nietzsche). It means that atoms and cells cannot be subjective. The operation of a human body (biological processes) cannot be subjective. All of the natural developments and phenomena are complex subjects. All in all, universal knowledge cannot be subjective because the only way to generate it is through empirical information, and empirical information is external, not internal (Nietzsche). In this way, subjective opinion (existential perspectivism) cannot help understand reality completely due to the complexity of this reality and the fact that a single subject does not exist. Conclusion That said, my belief is that Locke’s ideas can be applied to understanding simple ideas about reality, such as colors or weather. Instead, they are not helpful for obtaining knowledge about more complicated issues, such as cancer. Locke himself recognizes that his theory can be used for explaining the process of learning similar to that of children because it is based on observing the world. In this way, how does one know that cancer is a serious health concern if they have not faced it? By no means, if external data is not studied. However, external data is impossible to collect without conducting experiments or consulting educational materials that, in turn, are science. T