In this essay, I argue that human beings cannot possess absolute certainty about any claim concerning the world. What appears certain in one era often becomes untrue because of new data and perspectives. I take a skeptical approach to explore the relationship between certainty and knowledge. This position is influenced by philosophers such as Popper and Kuhn, who each challenge the idea that human knowledge can achieve absolute certainty (Kuhn, 1962/2012; Popper, 1963/2002). I argue that knowledge is constantly in motion, making notions of certainty improbable because it is directly linked to time and continually evolves through the eyes of those analyzing the universe. I contend that knowledge that seems stable is, in fact, only accepted because, at a specific moment, no more accurate explanation has been found and is therefore accepted as truth by default. I challenge the idea that certainty can be achieved through thought alone, which contradicts René Descartes. I support my position with philosophers who investigate the uncertainty of knowledge.

Knowledge changes, evolves, and conflicts across time and place. Some civilizations believe in different gods while observing the same natural phenomena. Over time, we have seen scientific understanding evolve from geocentrism to heliocentrism and from a flat Earth to a spherical Earth. In fact, scientific truths have continually evolved throughout history. Certainty was initially pursued through a more rationalist philosophy and later evolved toward a more empirical approach beginning in the seventeenth century. Regardless, these theories and observations established paradigms that were accepted as truth for a particular time and place. People followed these paradigms, and those who challenged accepted beliefs often faced social, political, or professional opposition. History contains many examples of individuals whose ideas were initially rejected before later becoming widely accepted. Over time, accepted truth in this knowledge diminished as new explanations emerged.

Karl Popper (1963/2002), in Conjectures and Refutations, illustrates that our scientific approach to determining certainty in knowledge depends on the methods used to evaluate truth. For Popper (1963/2002, p.36), no amount of confirmation can prove a theory true. A theory can only survive repeated attempts at falsification. Science therefore progresses not by establishing certainty, but by eliminating explanations that fail under criticism and experimentation (Popper, 1963/2002, p.37). Furthermore, Popper (1963/2002, p.33) argues that relying solely on confirmation can blur the distinction between science and pseudoscience. He uses astrology as an example of a theory that appears convincing because it can continually find supporting observations while avoiding meaningful attempts at falsification. Popper gives several examples in which science replaced previously accepted knowledge with theories that better explained observations. The transition from one accepted truth to another demonstrates that scientific knowledge remains provisional. What is considered certain today may later be replaced by a more convincing explanation.

In a similar line of thought, Thomas Kuhn, in The Structure of Scientific Revolutions, shows that science establishes accepted knowledge through paradigms (Kuhn, 2012, p.10). However, these paradigms evolve over time. Paradigms build upon one another until a revolution occurs (Kuhn, 2012, p.12). Certainties are challenged only when they become increasingly incompatible with reality. Consensus regarding paradigms is rarely unanimous and often contains assumptions that are overlooked until later discoveries reveal their importance (Kuhn, 2012, p.16). Divergence occurs depending on the scientists involved and the problems they face, creating new paradigms. Acceptance within the scientific community requires only that a new paradigm perform better than the previous one, not that it provide certainty (Kuhn, 2012, p.17). The approach focuses on a particular way of thinking, while investment in empirical evidence to prove absolute certainty or explore opposing views is often limited. The system does not encourage radically different thinking and has historically made it costly to become an outlier (Kuhn, 2012, p.20). Thus, established knowledge remains the status quo until existing paradigms become incapable of solving important problems.

Descartes (1641/1996) pursued skepticism to reveal what he believed was the only certainty: the Cogito (“I think, therefore I am”). By doubting everything that could possibly be doubted, including the evidence of the senses and even mathematical truths, he concluded that the act of thinking itself demonstrated the existence of a thinker. Unlike scientific knowledge, the Cogito does not depend on experimentation, observation, or induction. Instead, it is known directly through reason. A defender of certainty may therefore argue that the Cogito escapes the criticisms raised by Popper and Kuhn because it is not part of a scientific paradigm and cannot be tested through empirical methods.

However, even if thinking occurs, Descartes does not establish the permanence of the self behind the thought. The Cogito may demonstrate that a thought exists, but it does not necessarily prove the existence of a stable and enduring thinker. The conclusion assumes that the "I" remains consistent over time, yet questions regarding consciousness and personal identity continue to be debated by philosophers. Furthermore, history demonstrates that many ideas once regarded as self-evident were later reinterpreted through new perspectives and methods of inquiry. If our understanding of the self continues to evolve, then the certainty claimed by the Cogito may also be subject to reinterpretation. Therefore, the Cogito provides strong justification for belief, but it does not escape the possibility of future revision.

Historically, certainties have evolved into new ones. If we had a time machine, we would witness that, at every moment, people believed their knowledge was certain. A defender of certainty may argue that past mistakes do not imply that present knowledge is uncertain. However, every generation has believed that some of its beliefs were beyond doubt. The geocentric model, classical physics, and countless social and religious beliefs were all regarded as certain by many people in their respective eras. Because we cannot step outside our own historical perspective, we have no reason to believe that our present knowledge is exempt from future revision. While knowledge can become increasingly reliable and useful at a specific time, reliability should not be confused with absolute certainty. The history of philosophy and science suggests that certainty is often a temporary judgment rather than a permanent achievement. Human beings continually revise their understanding of the world as new evidence, methods, and perspectives emerge. What appears unquestionable today may become revised tomorrow, just as many previously accepted truths have throughout history. Therefore, the confidence we place in our present knowledge may also contain flaws and be revised in the future.

APA References

• Descartes, R. (1996). Meditations on first philosophy: With selections from the objections and replies (J. Cottingham, Trans.). Cambridge University Press. (Original work published 1641)
• Popper, K. R. (2002). Conjectures and refutations: The growth of scientific knowledge. Routledge. (Original work published 1963)
• Kuhn, T. S. (2012). The structure of scientific revolutions (4th ed.). University of Chicago Press. (Original work published 1962)