Lecture One

The principle of reason reads: nihil est sine ratione. One translates it: nothing is without a reason. What the principle states is illuminating. When something is illuminating, we understand it without further ado. Our understanding doesn't labor on in order to understand the principle of reason. How is this so? It is because human understanding, whenever and wherever it is active, always and everywhere keeps on the lookout for the reason why whatever it encounters is and is the way it is. Understanding looks for reasons insofar as it requires a specification of reasons. The understanding demands that there be a foundation for its statements and assertions. Only founded statements are intelligible and intelligent. Yet understanding requires reasons not only for its statements, but human cognition is already looking for reasons as soon as it dabbles in those things about which it might then make statements. In all that surrounds and concerns it, human cognition seeks reasons, often only the most proximate ones, sometimes even the more remote reasons, but in the end it seeks the first and last reasons.

This quest for reasons pervades human cognition even before it bothers with the founding of statements. The ubiquitous quest for reasons requires that one get to the bottom of what is encountered. Whenever we are getting to the bottom and founding things we find ourselves on the path to reason [Grund]. Without exactly knowing it, in some manner we are constantly addressed by, summoned to attend to, grounds and reason.

We are, in our conduct and cognition, on the way to reason as though this came about on its own. We constantly have, as it were, the principle of reason in view: nihil est sine ratione. Nothing is without reason. Our conduct everywhere takes into account what the principle of reason says.

Thus, in every instance where human cognition proceeds not only intelligently but with forethought, it cannot come as a surprise that eventually human cognition becomes explicitly aware that it follows what is stated in the principle of

The Principle of Reason (GA 10) by Martin Heidegger