Rationalism and post-modernism are two distinct epistemological movements that have a significant impact on the way the Western intellectual tradition is developing how we think about knowledge. The rise of "Fake news" and misinformation are attacks on our intellectual traditions, and scholars need to be concerned with the level of “Truth Decay” occurring in broader society. Kavanagh and Rich (2018) define “Truth Decay” as the diminishing role of facts and analysis in American public life, and that “the erosion of trust and respect for facts, data and analysis is often hamstrung by the use of conflicting language, unclear or undefined term, or words used to mean one thing by one group of people and something else by another.” (p. 18).

Rationalism is a philosophy that emphasizes the use of reason and logic as the primary means of acquiring knowledge, while post-modernism is a philosophy that critiques the idea of objective truth and argues for the importance of subjective experience and multiple perspectives.

Postmodernism, and its emphasis on the relative nature of knowledge, has firmly emerged during the past 30 years as an alternative epistemology to Rationalism. Postmodernism manifests in different ways, but it mostly reverts to relativism and subjectivity. Major proponents of postmodernism like Richard Rorty (1931–2007) even claim that epistemological relativism now reigns supreme (Hatcher, 1994). These postmodern constructs are in direct opposition to the logical positivism which is dominant in management studies and evidence-based management practices. Understanding this widening schism between rationality and postmodern epistemology has pertinent relevance for researchers, organizational practitioners and leadership in all walks of life.

Post-modernism challenges the notion of objective truth and instead emphasizes the role of language, power, and social constructions in shaping our understanding of reality. Murphy (2021) argues that many proponents of postmodernists have used Einstein’s Theory of Special Relativity to support their epistemic theories of relativism. Postmodernists claim that even in the natural world each phenomenon is not observed similarly by all. It depends on time and space. It is necessary to understand from where and when the phenomenon has been observed.

 However, Ozumba, et al. (2017) concluded that “most persons may interpret that Einstein is saying that everything in the universe is relative, but this work is of the position that everything is not relative, rather everything is relative from the observer’s frame of reference as posited by Einstein.” (p. 275).

The challenge is to find a balance between these two perspective, the rationalism's approach can be too rigid, and the post-modernism's approach can be too relativistic. However, a better understanding of these two epistemological approaches can lead to a more nuanced and holistic understanding of the world. Such an improved understanding should be based on (1) the importance and role of language (2) recognizing the dangers of individual bias, and (3) acknowledging that knowledge is iterative and always developing. Knowledge might be relative to a specific moment and space in time, but rather relative to an individual’s frame of reference at a specific moment and specific situation (space).