Why did Heidegger think practical involvement in the world is more basic than detached thinking?

Martin Heidegger argued that practical involvement is more basic than detached thinking because he rejected the traditional Cartesian view of the human individual as a "thinking subject" isolated from the world.12

Since the time of René Descartes, Western philosophy often assumed that humans are minds distinct from the material world, requiring mental states to bridge the gap between the subject and external objects. Heidegger inverted this perspective by defining the human individual as Dasein, or "being-there," which is fundamentally characterized by "Being-in-the-world".12

For Heidegger, human existence is not defined by internal awareness or abstract representation, but by being already caught up in, involved with, and committed to other individuals and things. Because our primary mode of existence is this active engagement, practical involvements are ontologically more basic than the detached, abstract thinking of a "thinking subject". Consequently, he prioritized concepts like "world," "everydayness," and "Being-with-others" to describe the fundamental structure of human existence, rather than starting from the assumption of an epistemologically isolated mind.2