Andrea asked:

I would like to know why a philosopher like Heidegger motivated such controversial opinions like the
one of Carnap and others. Which are the most important advances in his thought?

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The statement by Heidegger most frequently paraded around by logical positivists such as Carnap
and Ayer, as the supreme example of metaphysical nonsense, is 'Nothing Nuths' Das Nichts Nichtet,
taken from his Introduction to Metaphysics.I doubt whether any of them bothered themselves to
actually read the work.

David Farrell Krell gives a judicious summing up of Heidegger's contribution to philosophy in his
article for the Routledge Concise Encyclopaedia of Western Philosophy and Philosophersedited by
Urmson and Ree, 2nd Edn 1975:

Heidegger is without doubt the most powerfully original and influential philosopher of the century in
the Continental tradition. Phenomenology, existentialism and deconstruction are unthinkable without
him, but so are philosophy of literature and many social-critical or neo-Marxian strands of thought. His
importance in the English-speaking world is also growing steadily, because no other contemporary
thinker so unsettles the analytic enterprise. While convinced analytical philosophers fulminate against
him, or try to ignore him, their students have long been reading him.

For me, the most important advance in Heidegger's thought was his discovery of a new way of doing
metaphysics. Being and Time, published in 1927, ranks alongside the greatest works of twentieth
century metaphysics. It may not be easy going, but it is still a lot more readable than, say,
Whitehead's Process and Realityor McTaggart's Nature of Existence. In the phenomenological
tradition, Emmanuel Levinas Totality and Infinityis the only work of equal stature.

While Whitehead and McTaggart follow the traditional route of constructing a 'theory' of existence,
delineating the true structure of reality hidden behind, or only dimly perceived through the distorting
screen of ordinary language, Heidegger sees our actual everyday existence in the world, rather than
merely the things we say, or the concepts we use to categorize the things around us, as implicitly
involving a certain relation to reality, or 'Being'.

In Heidegger's picture, you and I do not merely hold a false view of reality, as Whitehead or
McTaggart would claim. Rather, we livea false, 'inauthentic' existence. This is not moralizing, nor is it
theorizing. It would be more correct to say that what Heidegger is looking for is a change of attitude
that would halt, and then reverse the process of the ever-increasing concealment of 'Being'. Being is
at least partially revealed when we rediscover the question of our own existence, in facing up to the
absolute inevitability of our own death. Therein lies the clue to the metaphysics of time. Just where
one goes from there, however, is not entirely clear. One gains the sense that Heidegger remains
absorbed with clearing away the obstacles in the way of Being, without a thought to what we would
actually see when the last obstacle is removed.

Geoffrey Klempner