This lecture course by Tom Bridges is useful in putting the historical context of Heidegger's understanding of metaphysics in What is metaphysics. That text is very austere and it is difficult to get a handle on it Tom's lecture course is useful as it locates Heidegger's text within the philosophical tradition. However, the text also represents an overcoming of the metaphysical tradition as its concern with anxiety opens up new ground.
Tom makes two points. The first is the Hegelian background to Heidegger's understanding of metaphysics. Tom says:
"We see in this text the influence of an Hegelian understanding of metaphysical inquiry....Hegel introduced historical reflection into metaphysical inquiry. For Hegel, the metaphysical inquirer cannot apprehend being or reality apart from the historical standpoint that he or she occupies. Particular historical standpoints are themselves manifestations or embodiments of being itself. Therefore, an inquiry about being as such is necessarily an inquiry about the historical manifestation of being embodied in the standpoint of the inquirer. This seems to be Heidegger's understanding of this own inquiry."
So how did Heidegger understand science in 1929? Tom says:
"Heidegger at this time followed his teacher, Husserl, in his belief that the sciences in the early twentieth century had lost their foundation. ..... it did....seem to many German academics between 1900 and the 1930s that there did in fact exist a "crisis of the European sciences" (the title of Husserl's last book). In this essay, Heidegger is reflecting that view. Very few philosophers or scientists still believed that the Cartesian project of seeking an absolute foundation for scientific knowledge was still viable. As a result, it seemed to them that the objectivity of scientific knowledge was no longer capable of proof. Science, therefore, seemed to be on the verge of losing its status as the paradigm of human rationality and objective or universally valid knowledge."
Tom says that Heidegger saw the crisis of the European sciences as an occasion to reopen what he called "the question of Being" -- he wanted to re-establish the sciences on their essential foundation by renewing the kind of metaphysical or ontological reflection found above all in Aristotle's writings.
It is a metaphysics of our understandings embodied in our everyday world, as opposed to a metaphysics of science.
Heidegger has a radical understanding of science. What Husserl thought of as the crisis of the European sciences Heidegger interpreted the crisis as the realization of the essentially technological nature of scientific knowledge. The Baconian conception of the neo-liberals who see science as a technological instrument to increasing the weath of the nation.
Heidegger distinquishes between scientific discourse and pre-scientific discourse and he explores the metaphysics of the pre-scientific discourse. Since the scientific attitude of impartiality and objectivity excludes the pre-scientific or our everyday conception of things, that leaves philosophy a space to explore the everyday conception of things. Heidegger does this in terms of doing metaphysics concerned with the nature of being through anxiety.
Anxiety is a good pathway to being because of the centrality of anxiety in everyday life. This editorial in The Age
"Last year, antidepressant drugs were prescribed to a quarter of a million Australian children and adolescents, which is 30,000 more than the number treated in this way in 2002.That so many young people are afflicted by anxiety disorders and other conditions treated by psychotropic drugs is in itself alarming and perplexing; that the drugs used to treat them sometimes carry risks of their own - risks that may outweigh the benefits of using them - is even more worrying.
In particular, clinical evidence overseas indicates that there is an increased incidence of suicide among adolescents taking the class of antidepressants called selective serotonin reuptake inhibitors."
Philosophy engaging with this situation of anxiety represents an overcoming of the metaphysical tradition.