Heidegger delivered this lecture on 4 August 1953. It is a meditation on the difference between science and mindfulness. Science is a decisive way in which all that is presents itself to us. It is the theory of the real. In this statement, the nature of science comes to light. What does the real mean, and what does theory mean?
The real is the working, the worked, the functional. It is that which brings forth into presence. The real presents itself as a stance in unconcealment. It stands over against and is therefore the object. In the modern age, the being of entities is objectness (Gegenständigkeit). As an object for a subject, the real becomes a representation.
The word theory stems from the Greek θεωρεῖν, which means the beholder that watches over truth. Theory understood in the modern way lives out of the former and has become observation. In observation, we pursue our object and try to entrap it in order to secure it. Theory makes secure at any given time a region of the real as its object-area. In the age of technology, the objectness of the real is secured as standing-reserve. Since each science objectifies reality in its own specific way, science, as such, can never represent objectness itself. This means that science can never arrive as its own presuppositions. We need to pay heed to this inconspicuous state of affairs. Precisely this state of affairs is worthy of questioning.
Mindfulness is the inceptual thinking that travels in the direction toward that which is worthy of questioning. Mindfulness proceeds by way of a self-awakening surrender to what calls for thinking, the truth of being.