This week, I’m blogging about my new book, The Epistemic Role of Consciousness (Oxford University Press, September 2019). Over the past three days, I’ve discussed the epistemic role of consciousness in perception, cognition, and introspection. In this final post, I want to explain how I integrate these claims about the epistemic role of consciousness into a unified theory of epistemic justification.
In Chapter 6: Mentalism, I argue for a version of mentalism that accommodates the epistemic role of phenomenal consciousness:
- Phenomenal Mentalism: Necessarily, which propositions you have epistemic justification to believe at any given time is determined solely by your phenomenally individuated mental states at that time.
Your phenomenally individuated mental states include not only your perceptual experiences, which are individuated by their phenomenal character, but also your standing beliefs, which are individuated by their dispositions to cause phenomenally conscious experiences of judgment. They exclude your subdoxastic mental states, which are individuated by their role in unconscious computational processes, and your externally individuated mental states.
Phenomenal mentalism is supported in a bottom-up way by the conclusions in the first part of the book. It explains why perceptual experience provides epistemic justification for beliefs about the external world and why unconscious perceptual information in blindsight doesn’t play the same epistemic role. It explains why your beliefs, as well as your perceptual experiences, can affect which propositions you have epistemic justification to believe. At the same time, it explains why your subdoxastic mental representations, unlike your beliefs, cannot affect which propositions you have epistemic justification to believe. And finally, it explains why you and your phenomenal duplicates in skeptical scenarios have epistemic justification to believe the same propositions to the same degree.
In Chapter 7: Accessibilism, I combine phenomenal mentalism with the version of accessibilism defined below:
- Accessibilism: Necessarily, you’re always in a position to know which propositions you have epistemic justification to believe any given time.
I argue that these views form a coherent package because phenomenal mentalism explains why accessibilism is true. Whenever you’re in some phenomenally individuated mental state M that gives you epistemic justification to believe that p, you’re thereby in a position to know the following:
- I’m in mental state M [by introspection]
- If I’m in mental state M, then I have epistemic justification to believe that p [by a priori reasoning]
- Therefore, I have epistemic justification to believe that p [by deduction]
If accessibilism can be motivated and defended on independent grounds, as I argue in the second part of the book, then phenomenal mentalism can be supported indirectly by inference to the best explanation.
Accessibilism provides the resources for an answering an explanatory challenge for phenomenal mentalism. What explains why only phenomenally individuated mental states are capable of affecting which propositions you have epistemic justification to believe? My answer appeals to a threefold connection between phenomenal consciousness, epistemic justification, and introspection. Given my version of accessibilism, a mental state provides epistemic justification for belief only if you’re always in a position to know by introspection whether or not you’re in that mental state. What’s special about phenomenally individuated mental states is that they are the only mental states that fall within the scope of what you’re in a position to know by introspection. This means we can supplement the bottom-up motivations for phenomenal mentalism with the following top-down argument:
- A mental state provides epistemic justification for belief only if it is introspectively luminous in the sense that you’re always in a position to know whether or not you’re in that mental state.
- Only phenomenally individuated mental states are introspectively luminous.
- Therefore, only phenomenally individuated mental states can provide epistemic justification for belief.
On this view, the epistemic role of phenomenal consciousness is to provide epistemic justification for belief in such a way that you’re always in a position to know by introspection and a priori reflection alone which propositions you have epistemic justification to believe at any given time.
Accessibilism also provides the resources for explaining and vindicating the conclusions in the first part of the book. Perceptual experience justifies beliefs about the external world only because you’re in a position to know by introspection that your perceptual experience has the phenomenal character in virtue of which it justifies beliefs about the external world. In contrast, unconscious perceptual information in blindsight doesn’t justify beliefs about the blind spot because it has no phenomenal character and so it falls outside the scope of introspection. Similarly, your beliefs justify holding other beliefs only because their contents are accessible to phenomenal consciousness and so you’re in a position to know by introspection what you believe. In contrast, subdoxastic mental representations don’t justify holding beliefs because their contents are inaccessible to phenomenal consciousness and so they fall outside the scope of introspection.
Much of the second part of the book is devoted to arguing for accessibilism and defending it against objections. One argument for accessibilism is an inference from its ability to explain intuitive judgments about cases. A second argument is that it explains the irrationality of epistemic akrasia. A third argument is that it captures a plausible connection between epistemic justification and reflection: an epistemically justified belief is one that has the potential to withstand ideal reflection.
I also defend accessibilism against a series of objections, including Timothy Williamson’s anti-luminosity argument, Ernest Sosa’s version of the problem of the speckled hen, David Christensen’s arguments from misleading higher-order evidence, Hilary Kornblith’s arguments against the importance of reflection, and Eric Schwitzgebel’s arguments against the reliability of introspection. A central theme in my responses to all these objections is that we need to be sensitive to the distinction between epistemic ideals and psychological reality.
My overall goal is to resuscitate a broadly Cartesian picture of the role of consciousness in epistemology and the philosophy of mind. But I have tried to execute this project in a way that is compatible with a realistic psychological understanding of ourselves as creatures whose reasoning is often unreflective and only imperfectly sensitive to the evidence provided by our conscious and consciously accessible mental states. I hope you will read the book in order to judge for yourself whether or not I have succeeded in this aim.