Thursday 3/7
Consciousness I: The (Hard) Problem
Assignments
Readings
Texts
- Thomas Nagel, "What is it Like to Be a Bat?"
- David Chalmers, "Consciousness and Its Place in Nature"
Notes
Synopsis
Although not in this essay, David Chalmers elsewhere draws a useful distinction it is important for us to bear in mind. Thus far we have been concerned with the problem of original intentionality, which bears on mental states insofar as they are functional states--that is, insofar as they play roles in the mental economy or how the mind does what it does. For example, my belief that it is raining today, along with my desire to stay dry, explain my grabbing an umbrella on the way out the door. Beliefs, desires, and intentions play specific roles in the mental economy, just as dollars and euros do in the international economy.
There is, however, another side to mental states: There is something it is like to have them. To want a glass of red wine is, on the one hand, to have a desire for the glass, and, on the other hand, to feel the pull, if you will, of the red wine. There is further something it is like to actually drink the red wine and satisfy the desire for it. These raw feels or qualitative experiences associated with mental states collectively fall under the problem of phenomenal consciousness. Why, in a nutshell, should there be anything it is like to be in a mental state of any sort?
The problem of phenomenal consciousness is usually cast as a problem for physicalism: At least some mental facts--facts about phenomenal consciousness, in particular--are not physical facts; hence no version of physicalism, including machine functionalism, is true. Thus phenomenal consciousness is opaque to science, since science only trades in physical facts. Put another way, science cannot explain how phenomenal consciousness emerges in a purely physical universe.
The problem phenomenal consciousness presents is as simple as it is devastating. As Nagel points out, no study of bats can ever reveal what it is like to be a bat. As much as we might learn about echo-location and nocturnal navigation, a bat's phenomenal consciousness is intrinsically perspectival: We can never know what it is like without already having that perspective, which we would have only if we were already bats ourselves.
It is no surprise to find that the problem is equally pressing for our project of understanding the mind 'vis a vis' Dretske's Dictum. Roughly put, there is nothing it is like to be a Turing Machine. If phenomenal consciousness is not physically accessible, then it's not computationally accessible, either. Searle's response to the Robot Reply to the Chinese Room Thought Experiment anticipates this point, for it is clear that Searle-in-the-Robot sees nothing the Robot's video cameras record, hears nothing the Robot's microphones pick up, and feels nothing the Robot's tactile sensors contact. Searle sees, hears, and feels nothing in the Robot's environment because all he is doing in the Robot is transforming strings of symbols (data-streams) as they are generated by the Robot's cameras, microphones, and tactile sensors. So even though there is something it is like to be Searle himself as he sits there in the Robot furiously transforming strings of symbols into other strings of symbols according to specific rules, there is nothing it is like to be Searle-in-the-Robot inasmuch as he is necessarily blind, deaf, and numb to the Robot's environment.
If this is an appropriate extension of the Chinese Room Thought Experiment to the problem of phenomenal consciousness, then it follows that robots are necessarily philosophical zombies. That is, regardless of the variety and sophistication of its behavior, there cannot be anything it is like to be a robot.
This is the hard problem of consciousness: For creatures like us there is something it is like to be, just how is there something it is like to be them? How does a squishy lump of greyish/whitish matter have phenomenal consciousness insofar as it is not merely aware of things in its environment, it has experiences of them as having various qualities?
Over the next few weeks we will underscore the seriousness of these questions by examining in some detail three kinds of arguments which appear to show that there is a fundamental gap between the physical (or the computational) and the phenomenal:
- The Knowledge Gap
- The Modal Gap
- The Explanatory Gap
Each set of arguments start from wholly distinct assumptions but disconcertingly converge on the conclusion that phenomenal consciousness, a capacity we all take for granted even as we value it more highly than anything else in the Universe, is not itself a physical process of any sort. We begin after Spring Break with The Knowledge Gap.