Hubert Dreyfus & Heidegger - is Heidegger a dualist?

Question

Heidegger rejects Cartesian dualism... but this video with Hubert Dreyfus confuses me:

https://www.youtube.com/watch?v=G24JBUh4yVg

At 9:00, he implies that according to Heidegger, physics can't explain Dasein. Doesn't that make Heidegger a dualist? Or is he saying that the physical world can be explained in terms of Dasein?

By dualist, I mean either a substance dualist or a property dualist.

Answer 1

Thanks for the referred video. I cannot agree more with l_ruth on the interpretation of what Dreyfus was saying. I post this answer since I do not think l_ruth's response is sufficient to answer the question by Ameet Sharma. The question that needs an answer is this:

According to Heidegger, physics can't explain Dasein. Doesn't that make Heidegger a dualist? Or is he saying that the physical world can be explained in terms of Dasein?

To answer the question, some preliminary is necessary.

1. Dasein means (the mode of) human existence, a la Heidegger. Heidegger postulates that we humans are the only entities that can ask the question of our own existence as well as existence itself. Neither dogs nor ants can ask that kind of question. For this reason, Heidegger thinks that knowing about human existence is the only window to know about the existence itself.
2. A (Cartesian) dualist holds the view that the world is composed of things that extend and things that think.
3. Heidegger famously rejected the Cartesian dualism. To Heidegger, we humans as beings are necessarily situated in the spatio-temporal coordinate (or beings-in-the-world, a la Heidegger). Separating oneself from the world, i.e., the stage for the Cartesian skepticism, is impossible.
4. Dreyfus is well known for his anti-AI view, that is, it is impossible for machine intelligence to be equivalent to human intelligence.

Given these, let's answer the question. Dreyfus’ Heidegger argues that science cannot explain the mode of human existence. Indeed Heidegger argued that the human condition is known analytically, by “existential analytic of Dasein” (https://plato.stanford.edu/entries/heidegger/) So Dreyfus' Heidegger rejects physicalism and materialism (views that try to explain mental phenomena by means of science or by res extensa). Rejecting physicalism does not make Heidegger a dualist. Why? Ameet Sharma is in the right direction since Dreyfus' Heidegger thinks that the physical world can be explained only in terms of Dasein. (see 1)

In the video, Dreyfus is forced to answer how scientific realism is possible under the Heideggerian view, or more specifically, under the Husserlian phenomenological method (an alternative way to understand the physical phenomena) which Heidegger adopted. The potential problem raised for Dreyfus is that if scientific realism is true, then the above 3 (beings-in-the-world) cannot be true. I think Dreyfus's answer is brilliant, which we can only observe from a philosopher master (Professor Hubert Dreyfus passed away this year (2017). Ah Time, that completes us all!). Dreyfus says that it is indeed scientists’ job to explain the natural phenomena, but it is thanks to the phenomenology that warrants the doings of scientists.

Answer 2

I do not think Dreyfus says that physics itself cannot explain Dasein - I think he says that we need to be careful not to conflate our method of discovering natural kinds in the world with having discovered an explanation for Dasein itself, and that that is irreducible to our method, whereas in the history of Western ontology philosophers have tended to conflate their discovery of a method with a full and sufficient explanation for the existence of Dasein itself.

Answer 3

@AmeetSharma I do not think Dasein is reducible to natural kinds, so I do not think Dasein is explainable by physics ... Though natural kinds may be discoverable by science, and physics may involve a valid method of discovering facts about existence, Dasein will never be reducible to what we can discover by any method, because it exists independently of physics and every other science for that matter.

I think Heidegger's positive argument may be operating at a "level above" the debate between dualism and materialism about existence. This debate, perhaps, could be seen as a symptom of Western ontology's attitude of presumption towards existence, that once we have found a way of discovering something about it through science, then the importance of existence itself is reducible to the importance of science for us - whereas, for Heidegger, perhaps this is like looking at existence backwards, through the arbitrary lens of our valuing it according to its "instrumentalisation" value.

One useful thing to remember could be that Dasein is a concept Heidegger apparently uses to critique Western ontology, and though there may be a positive project inherent within it, he is deliberately not buying into already-established debates about the reduction of existence into one thing or another - the-way-things-are-in-the-world is, completely independently of applying our minds to understanding facts about it.

I hope this helps in answer to your response to my first comment!