Heidegger refuses to come out and tell us what it means, in any definite sense, to Think.
He does, on the other hand, supply us with plenty of examples of what Thinking is not, but that we may think that Thinking is, because thinking has been thought of in various ways throughout history.
Plato establishes a duality between the chair that appears, the physical chair, and the metaphysical Chair through which all chairs receive their chairness by participating in the ideal Chair.
Thinking, for Plato, does not deal with the actual physical chair in front of us, the truth of the chair does not reside there, but somewhere else, somewhere eternal and unchanging.
This is the demand that rational thought places upon an encounter with a tree, we let the thing be determined from out of the mode of eternalized essences, whether we appeal to a dictionary definition of a tree or think that the essence of matter is atoms and molecules and forces at play.
There is the appearance of the tree and there is what the tree really is, behind the appearance.
The German philosopher Martin Heidegger died in 1976, yet scholars are still plowing through his life’s work today -- some of it for the very first time.
And although Heidegger’s work is most firmly entrenched in the Western tradition, his readership is global, with serious followings in Latin America, China, Japan, and even Iran.
The book, however, defies systematization before it even begins, the title itself rings out in ambiguity, it is usually translated as “What is Called Thinking”, but could just as easily be translated as what calls for thinking, what has been called thinking, or what is called for in order to think rightly.
Heidegger asks his reader to stay with the ambiguity of the question in the title, which “can never be answered by proposing a definition of the concept , and then diligently explaining what is contained in that definition.” Instead, he wants to lead us to where we can make the leap ourselves into thinking.