The prior probability of 1 in 10^7 is already lower than I can handle in a well calibrated manner, and it would only get smaller after accounting for the evidence that I observe my left arm moving when I try to move, and I am successfully using it to type right now, and from the descriptions I read, anosognosiacs do not claim to make these observations, but attempt to make excuses for the lack of such observations.

In any event, it is not something I am too concerned about.

I wonder if the paradoxical undressing effect is a form of anosognosia.

Paradoxical undressing is when the person removes warm clothing while in a state of hypothermia, which further increases heat loss. Because they are suffering from the cold and their body temperature is below the safe threshold, it seems incongruous that they would be removing warm clothing and causing themselves to become even colder.

To be sure, the phenomenon of paradoxical undressing is an enigma counter to expected behavior. With their core temperature below 90 degrees F, hypothermia sufferers frequently undress themselves. Urban victims of hypothermia that are found in a state of undress are often thought to be victims of assault.

Paradoxical undressers remove their warm clothing even as they are freezing to death.

Suppose I put in a nerve block to artificially paralyze my left arm, and I notice that my left arm is indeed paralyzed. I then remove the nerve block and notice that my left arm is no longer paralyzed. Would that be sufficient to prove (to myself) that I don't have left-arm paralysis with anosognosia?

BTW, I'm not sure I understand the current fascination on this blog about anosognosia. Where is this train of thought going?

I'd expect that for a rationalist afflicted with anosognosia, denial would manifest itself in the form of absurdly low base rate estimates, maybe one in a thousand or rarer.

It seems that if I were an anosognosic, I would make some observations only indirectly related to the affected limb that they don't seem impaired at making. For instance, even if I didn't notice that I was typing with one hand, I would probably remember having been to the hospital, or hearing a friend point out that one of my limbs looks awfully limp (even if I didn't know what they were talking about). Since I haven't made such observations, my probability that I'm anosognosic (at least about a limb or anything that observable) is lower than the prior.

1 in 10 million is almost low enough for me to feel annoyed that this article exists.

And people actually play the lottery!

I guess I can imagine someone being awakened by your analogy. It would be swell if this article actually had enough millions of readers that we might experience some spectacularly delusional one-handed comments.

Does the absence of people around me pointing towards my arm insisting it does not move, while believing that I have done plenty of activities in which I used 2 arms mean I am an extreme Anosognosic. One who rewrites massive quantities of 1 arm experiences to 2 arm experiences on the fly?

Hrm... I wanted to say 10^-7, but then I realized I actually do have evidence that is different from the type of false justifications associated with anosonosia.

The latter, as I understand it, tends to be associated with making excuses for why one isn't moving the arm, etc... I notice though that I actually can move my arms. That is, I observe myself waving both arms freely, typing using both hands, etc.

I'd have to spend a bit more type to work out reasonable numbers associated with it, but these observations are different from the "making excuses for why one can't move the arm in question"

See Added: "This interests me because it seems to be a special case of the same general issue discussed in The Modesty Argument and Robin's reply Sleepy Fools - when pathological minds roughly similar to yours update based on fabricated evidence to conclude they are not pathological, under what circumstances can you update on different-seeming evidence to conclude that you are not pathological?"

1 in 10,000,000. If I decrease that estimate I must increase it and vice versa.

Given the odds of 1 in 10 million, I'm confident that not only am I free of this condition, but no one I've ever met has it either. I'm not even going to take a typing test to prove that I still type at 70wpm (which may be possible to do with one hand, but I don't think anyone could learn it without being conscious of having done so). I will reevaluate this conclusion if a doctor (or anyone, really) tells me they think my left arm is paralyzed.

EDIT: As for an exact number, I am > 99% confident about this, which is high enough that it is not worth it to calculate a better estimate.

Some evidence supporting me having both fully functional hands:

• I'm good at typing. In particular I beat all my friends' scores at Facebook's Typing Maniac game, what a few of them find highly annoying and tried to beat my score. If I was paralyzed that would imply all my friends are also paralyzed, or truly outrageous at typing, or alternatively I came up with some amazingly efficient way of one-hand typing that beats normal two-hand typing.
• I play a lot of first person shooter games which by design require use of both hands, and some other games that require use of both mouse and keyboard. On the other hand I tend to suck at multiplayer mode, so perhaps I only imagine being good at them.

Can anosognosia patients remember being in a hospital, being told that they are paralyzed or failing at a simple two-handed task? I don't remember any of those things. I'm even writing this last sentence while holding my keyboard up in the air.

From the popularity of the "Strangest thing an AI could tell you" post, and anosognosia tidbits in general, this topic seems to fascinate many people here. I for one would find it freakishly interesting to discover that I had such an impairment. In other words, I'd have motivation to at least genuinely investigate the idea, and even accept it.

How I'd come to accept it, would probably involve a method other than just "knowing it intuitively", like how I intuitively know the face of a relative to be that of a relative, or how I know with utter, gut level certainty that I have three arms. Considering that we are, well, rationalists, couldn't we be supposed to be able to use other methods, to discover truth, than our senses and intuitions ? Even if the truth is about ourselves, and contradicts our personal feeling ?

After all, it's not like people in the early 20th century had observed tiny pictures of atoms, they deduced their existence from relatively nonintuitive clues glued together into a sound theoretical framework. Observing nature and deducing its laws has often been akin to being blind, and yet managing to find your way around by using indirect means.

If I had to guess, I'd still not be certain that, even being a rationalist using scientific methods and all those tools that help straighten chains of inference, as well as finding anosognosia to be more of a treat than a pain to be rationalized, would make it a sure bet that I'd not yet retain a blindspot.

Maybe the prospect of some missing things could be too horrid to behold, not matter how abstractly, perhaps beholding them may require me to think in a way that's just too complicated, abstract and alien for me to ever notice it as being something salient, let alone comprehensible.

Still that's really not what my intuition would lead me to believe, what with truth being entangled and so forth. And such a feeling, such an intuition, may be exactly part of the problem of why and how I'd not pay attention to such an impairment. Perhaps I just don't want to know the truth, and willingly look away each time I can see it. Then again, if we're talking rationalization and lying to oneself, that has a particular feeling, and that is something one could be able to notice.

Evidence that I have anosognosia: my left arm doesn't seem to be paralysed to me; if it did, I'd be sure I don't have anosognosia.

Evidence that I don't have anosognosia: the title of this post (see Betteridge's law). :-)

My estimated probability is too low to consider alone without additional evidence. I like this probability. If you require a number, 1/10,000,000.

Now, I currently appear to be typing with both hands, and there is nobody else in sight. Does this evidence lower the probability that my left arm is paralyzed as much as you might expect? If my left arm is paralyzed, there's a good change that this is just a rationalization.

See if you can think of a statement S that contradicts a statement of high probability such that no observable phenomenon is evidence against it. (Of course, nothing will be evidence for it, either.)

let's say the base rate is 1 in 10,000,000 individuals
Supposing this to be the prior, what is your estimated probability that your left arm is currently paralyzed?

1 in 10,000,000