Chapter 3. Understanding and Being

3.1 Hermeneutics

3.2 Understanding and ontology

p 30-31

The prevalent understanding is based on the metaphysical revolution of Galileo and Descartes, which grew out of a tradition going back to Plato and Aristotle. This understanding, which goes hand in hand with what we have called the ‘rationalistic orientation,’ includes a kind of mind-body dualism that accepts the existence of two separate domains of phenomena, the objective world of physical reality, and the subjective mental world of an individual's thoughts and feelings. Simply put, it rests on several taken-for-granted assumptions:

1. We are inhabitants of a ‘real world’ made up of objects bearing properties. Our actions take place in that world.
2. There are ‘objective facts’ about that world that do not depend on the interpretation (or even presence) of any person.
3. Perception is a process by which facts about the world are (sometimes inaccurately) registered in our thoughts and feelings.
4. Thoughts and intentions about action can somehow cause physical (hence real-world) motion of our bodies.

Much of philosophy has been an attempt to understand how the mental and physical domains are related—how our perceptions and thoughts relate to the world toward which they are directed. Some schools have denied the existence of one or the other. Some argue that we cannot coherently talk about the mental domain, but must understand all behavior in terms of the physical world, which includes the physical structure of our bodies. Other espouse solipsism, denying that we can establish the existence of an objective world at all, since our mental world is the only thing of which we have immediate knowledge. Kant called it "a scandal of philosophy and of human reason in general" that over the thousands of years of Western culture, no philosopher had been able to provide a sound argument refuting psychological idealism—to answer the question: "How do I know whether anything outside of my subjective consciousness exists?"

Heidegger argues that "the ‘scandal of philosophy’ is not that this proof has yet to be given, but that such proofs are expected and attempted again and again.". He says of Kant's "Refutation of Idealism" that it shows "...how intricate these questions are and how what one wants to prove gets muddled with what one does prove and with the means whereby the proof is carried out."

3.3 An illustration of thrownness

3.4 Breaking down and readiness-to-hand