"It ought to arouse our suspicions that people who spend enormous efforts on interpreting [Martin Heidegger's] work disagree on the fundamental question whether he was an idealist. For the purposes of this discussion, his lack of a resolute commitment to the basic facts is enough. Suppose you took the notion of Dasein seriously, in the sense that you thought it referred to a real phenomenon in the real world. Your first question would be: How does the brain cause Dasein and how does Dasein exist in the brain? Or if you thought the brain was not the right explanatory level you would have to say exactly how and where Dasein is located in the space time trajectory of the organism and you would have to locate the right causes, both the micro causes that are causing Dasein and its causal effects on the organic processes of the organism. There is no escaping the fact that we all live in one space-time continuum, and if Dasein exists it has to be located and causally situated in that continuum. Furthermore, if you took Dasein seriously you would then have to ask how does Dasein fit into the biological evolutionary scheme? Do other primates have it? Other mammals? What is its evolutionary function? I can’t find an answer to these questions in Heidegger or even a sense that he is aware of them or takes them seriously. But taking these questions seriously is the price of taking Dasein seriously, unless of course you are denying the primordiality of the basic facts."