And it's all around us
as ghosted machines […]
And as much as I'd like to
believe there's a truth
about our illusion,
well, I've come to conclude
there's just nothing beyond it
the mind can perceive
except for the pictures
in the space in between.
Jan Blomqvist, The Space In Between
I have been a cartesian dualist since I was a teenager. What else can you be, apart from a solipsist? [that strictly carried out coincides with pure realism]. For most of my life I used to think that physicalist dualism was the consensus of analytic philosophers (as it is among hard science fiction writers). Then, I decided to write a booklet of philosophy for Economists, and I began by a literature review of what I expected to be the standard scientific-philosophical cosmovision, based in three pillars: subjectivism, emergentist physicalism, and epiphenomenalism.
But I was surprised to discover that (at least explicitly) the “standard” philosophy was not so standard: it was named “Naturalistic Dualism”, and its canonical text is “The Conscious Mind”, authored by the Australian Philosopher David Chalmers. I found the book correct, and probably definitive, but too long: Chalmers delves in any possible objection to this otherwise supremely clear philosophy, and that detracts from persuasive power and clarity.
In the age of internet, where the 10-pages essay is King, I finally decided not to write a booklet, but an essay, whose final version was published a few days ago in Journal of NeuroPhilosophy (I want to thank the participants in the Less Wrong post that helped to improve the original article, and the editors of the Journal).
In “Freedom under Naturalistic Dualism” you will find a short piece both introducing, and I hope clarifying Naturalistic Dualism:
First, I wanted to underline that epiphenomenalism is compatible with freedom. While our mind emerges from physically determined and autonomous matter, our experience and its physical substratum are synchronized. Your experiential account of your actions and their internal coherence are the result of a physical process, but the mental process can be logical and true. Freedom is part of the conscious experience and as such is a legitimate concept: by evaluating the set of possible futures conditional on their actions, a conscious subject constructs a mental object that defines the scope of their “freedom.” If agency is the “power to act,” then a conscious being who can choose among several options possesses this power, regardless of how determined the use of that power may be, vindicating Schopenhauerian free will.
I believe Chalmers' "p-zombie conceivability" argument is valid, but it may not be entirely convincing. The essence of Naturalistic Dualism is that there is no "hard problem of consciousness": consciousness is a fundamental fact, and we should adhere to Newton's "hypotheses non fingo" regarding fundamental facts. However, the "pretty hard problem of consciousness" (finding a method to quantify the intensity of consciousness emerging from a physical system) is entirely real and somewhat insurmountable. Even Laplace's Demon (the most phenomenally knowledgeable possible being) is unable to assess consciousness. In the context of Artificial Intelligence, we find ourselves in a similar position to Laplace's Demon: we possess the perfectly predictive source code, but we lack the means to utilize this complete scientific knowledge to assess consciousness.
Beyond your own mind, consciousness is not "proven" or "observed" but postulated. We have direct access to our own stream of consciousness and given our physical similarity to other humans and the existence of language, we can confidently accept the consciousness of others and their reports of mental states. All promising research programs on the mind-body problem, (collectively known as "neural correlates of consciousness") rely on a combination of self-reporting and neurological measures. As an external observer of this literature, I believe that the empirical "Information Integration Theory" (IIT) has achieved remarkable success. The development of a predictive model, as described in "Sizing up Consciousness" by Massimini and Tononi, has been able to distinguish between conscious (vigil and dreams) and non-conscious (dreamless sleep) states through neurological observation using a (crude) measure of information integration.
A crucial observation about freedom is its relationship with time: in our Universe (where the past is remembered and the future unknown) freedom (and will) is always oriented towards the future: if freedom is the set of possible “states of the world” conditional on the subject’s actions, and the subject’s actions cannot affect the past, freedom with respect to the past is inexistent. The relation between prescience and will (that is an instance of the time/freedom relation) is a classic issue in science fiction: it is a central theme in Dune (where the treatment is more dramatic than logical) and it is explored in mechanical detail in Robert Silverberg’s “The Stochastic Man” and in the short story “History of your life” by Ted Chiang. Physicalists are divided between determinists that believe in the “time block universe” (vg. Ted Chiang), where there is single future that our conscious experience travels through, and non-determinists, who believe that the fundamental laws of physics include irreducible or ontic randomness. Ontic randomness immediately implies time asymmetry: in my view God plays (ontic) dice with the Universe, and that is why we do not remember the future. Some recent work by the Polish Physicist Johanna Luc suggest this is the most plausible interpretation of quantum measurement.
But of course, if philosophy is a branch of fantastic literature, as J.L. Borges so brilliantly perceived, why not going to the root too?
The best ever science fiction writer is another Australian, Greg Egan (I love his website so much), and the Mind-Body problem is precisely his main interest. There are two exceptional collections of short stories, named “Axiomatic” and “Diaspora” that while readable and pleasant also work as the “problem sheets” for the “the Conscious Mind” (if you are a mathematician, you know that problem sheets are as important as the textbook). In this regard, there are two short stories that I recommend for the beginning of your journey into Naturalistic Dualism:
It is perfect if you read them while you listen Jan Blomqvist’s melodic techno. Regarding the Conscious Mind, he is one of the best practitioners ever.