Why did Heidegger argue that philosophical knowledge is not the model for all knowledge?

Martin Heidegger argued that philosophical knowledge is not the model for all knowledge because he rejected the long-standing Cartesian tradition—spanning from René Descartes to Immanuel Kant and Edmund Husserl—that viewed the human individual as a detached, "thinking subject" isolated from the world.12

In his work Being and Time, Heidegger contended that this epistemological focus on theoretical, individualistic cognition is derivative rather than primary. Instead, he argued that human beings are fundamentally "Being-in-the-world," meaning they are always already engaged in practical, communal, and sociocultural involvements.231

For Heidegger, the primordial way humans interact with their environment is through practical activity—much like a workman using tools—rather than through the specialized, theoretical reflection characteristic of a philosopher or scientist. By elevating philosophical abstraction as the paradigm of knowledge, traditional epistemology failed to recognize that such thinking is merely a specialized, secondary mode of cognition that presupposes our more basic, prereflective engagement with the world.2