Abstract:
A 1% skeptic is someone who has about a 99% credence in non-skeptical realism and about a 1% credence in the disjunction of all radically skeptical scenarios combined. The first half of this essay defends the epistemic rationality of 1% skepticism, appealing to dream skepticism, simulation skepticism, cosmological skepticism, and wildcard skepticism. The second half of the essay explores the practical behavioral consequences of 1% skepticism, arguing that 1% skepticism need not be behaviorally inert.Full version here.
(What I mean by crazy metaphysics.) (What I mean by disjunctive metaphysics.)
As always, comments/reactions/discussion welcome, either as comments on this post or by direct email to me.
ReplyDeletepositive empirical [...] reason to assign some non-trivial credence to the possibility that the universe contains many sims...
But all the reasons I can think of for being confident that I’m awake seem to admit of some doubt...
My only thought reading this is the problem of self-undermining, which you do allude to, but then undermine by using language like that above. That is, I can't see how there can be empirical reasons to entertain the simulation hypothesis. In the same way, the experience you label dreaming is undermined as being relevant to anything - you only dream that you are dreaming? Assigning measures of credence seems to be dissolved by this kind of skepticism - 1% chance that probability is meaningless. I am a little suspicious of the concept of Knightian uncertainty, but this is one step worse.
David, I like that you're pushing back a bit on this, but your comment is too compressed for me to see what your argument is or exactly where you think the flaw in my argument is. Spell it out a bit more?
ReplyDeleteSimply that there is no way to avoid a slippery slope re dream skepticism - although I personally carry out correct mental calculations regarding probabilities in my dreams, it is not much of a stretch to suggest that your credence estimates will only hold if they are made when you are awake.
ReplyDeleteWith regard to simulation, the only objective evidence that one would trust would be that confirmed by other observers - otherwise the assumption of mental illness should always be more likely. And this too can be undermined by expanding skepticism.
I notice you also gracefully skate over the question about revision of credences with repeated flying experiments ;)
"Dreams are nothing marvellous. Any idiot can dream while the Father of Cats and his creatures, the Laughing Dervishes, make monkeys of us all..."
Re: your conversion to agnosticism, wouldn't you still qualify as a functional atheist? I'm reminded of something Dawkins said, possibly in the god delusion, that on a scale of 1 to 7, 1 being a true believer and 7 a complete atheist, he was a 6.9 atheist. I'm not knocking your argument, it's just that from what little I've read by agnostics, they tend to balance the probabilities around 50:50 between materialism and the loosest form of deism, more or less sitting on the fence. But maybe I've misread them.
ReplyDeleteI think your thesis has some interesting applications outside this particular debate. How about morality, for instance? The main debate, I guess, would be between realists and anti realists. However, unlike the metaphysical issues in your essay, I don't see any position as having enough plausibility to claim the 99% credence of your 1% skeptic. Would
also be fun to apply to political positions. Is there such a thing as a 5% fascist?
Btw, how does Bayesianism figure into all this? Beyond the obvious use of priors and probabilities, I mean. Do you think Bayesian epistemology is the only game in town, or is your position more subtle than that?
David: I fear we have descended to the ape-level!
ReplyDeleteJuan: I'm not sure exactly where to draw the line between "atheist" and "agnostic", but I do think that my current approximately 5% credence in some sort of god is pretty different from my previous 0.1% credence, in that I feel much less dismissive of theism than I did. This seems to me a qualitative change of some sort. Certainly too -- probably at least as commonly -- there are agnostics of the sort you describe.
On applying to other issues: I entirely agree. My forthcoming essay "The Crazyist Metaphysics of Mind" defends the rationality of leaving substantial credence space in metaphysics of mind for a variety of options rather than going whole-hog materialist. And probably one could to something similar in ethics, political philosophy, or meta-ethics, perhaps with substantially different consequences than one would embrace with a simple on/off acceptance of one's preferred position.
On Bayesianism: I'm obviously sympathetic to some of the basic ideas, but the simplest versions of it seem to me to face difficulties, e.g., in dealing with irrationality, non-omniscience, the discovery of new possibilities, the setting of priors, imprecision, and shifts other than by exposure to new evidence. I tend to be a pragmatic pluralist both about formal systems and about models of human cognition.