[jpttsn]

Many may be, but as other comments state, arguments against solipsism don't all rely on behavior/performance:

Some non-Turing test arguments against solipsism.

- Humans are believed to be similar to me in origin

- Humans are made of the same physical stuff that I am made of

I personally think none of these conclusively solve the hard problem but they can motivate belief if you so choose.

Even so,

Requiring a Turing test to believe other humans as thinking/conscious seems uncommon to me. I don't think many people live in solipsistic doubt about other humans, and I don't think they actually test behaviors to convince themselves humans are conscious.

So I don't know if they're tacitly accepting the behavior as useful for categorization; I think they're mostly just assuming "humans == conscious" and if pressed will come up with behaviors-based explanation because that's easy to formulate.

[mannykannot]

I see that I will have to expand on my brief observation, but to get us on the same page, I will need to know what you mean by the premise "humans == conscious".

If this is to be taken as a statement of identity, I would regard it as a category error, but I will not expand on that here, as I doubt it is what you intended.

If it is to be taken as the claim that only humans could be conscious, I would regard it as both lacking any justification and begging the question.

I think you mean that people generally assume everyone else is conscious in much the same way as they themselves seem to be, which is essentially saying they hold a theory of mind. If so, then I agree with you, but where do we get it from?

I know of no argument that we are born holding this theory, and it seems implausible that we are, as we are born without sufficient language to know what it means. False-belief tasks suggest that we begin to develop it at about 15 months (they also suggest that some other animals have it to some extent.) At that age it is, of course, tacit (rather than propositional) knowledge.

It would be absurd to suggest that toddlers come to deduce this from some self-evident axioms. What does that leave? I don't think there are any suggestions other than the obvious one: we arrive at it intuitively from our observations of the world around us, and particularly other people.

Ergo, those of us who make use of a theory of mind came by it from observation of what you call "a fuzzy indirect set of second-order human behaviors", and no one, as far as I know, has come up with a better justification for believing it.

[jpttsn]

Yes, I meant to write ”human => conscious.” Theory of mind.

To the extent theory of mind is learned it’s obviously learned from “a fuzzy…”. No disagreement there. What’s your point?

My point was more that it’s usually not a Turing test; my grandma has never thought explicitly about any kind of test criteria for determining if theory of mind applies to my grandpa. She just assumed as people do.

People believe things without justification all the time. Even if obeserved human behavior is the best justification for ToM, doesn’t mean that’s the one any human used.

I don’t think we disagree about anything meaningful?

I’m not confident what causes theory of mind. But I think it’s very rarely propositional knowledge even in older humans.

Is theory of mind re-learned by each human individually from observations? You seem to make the case for this?

Theory of mind could also be innate; I’m not so convinced about the role of nurture in these things. I know people who are afraid of snakes yet have never encountered snakes.

[mannykannot]

> What’s your point?

Well, let's go back to my original post in this thread, replying to one where you concluded with "until we know much more about the insides of minds, the 'all observable properties' is a fuzzy indirect set of second-order human behaviors." This statement, like your comments generally, is obviously made under the assumption that other people have minds, and my observation is that, as far as I know, there is no basis for that assumption other than what you call "a fuzzy indirect set of second-order human behaviors." Therefore, each of us individually is faced with a quadrilemma (or whatever the proper term is:) 1) Reject this fuzzy evidence, embrace solipsism, and cease assuming other people are conscious until we have a justification that avoids these alleged flaws; 2) Contingently accept, at least until we know more, the fuzzy evidence from human behaviors as grounds for thinking other people are conscious; 3) Inconsistently reject the fuzzy evidence without realizing that this currently leaves us with no basis for rejecting the solipsistic stance; 4) Like grandpa, don't pursue the question, at least until someone else has figured out more than can be learned from fuzzy observations of human behaviors.

You have suggested that our theory of mind is innate. This is not an unreasonable hypothesis, but I would like to raise two responses to that view, the first suggesting that it is implausible, and the second showing that it would not help your case anyway.

The first is the aforementioned evidence from false belief experiments, which strongly (though not conclusively) suggest that a theory of mind is learned (though ethical considerations limit how far such studies can be taken on human infants.) The existence of an innate fear of snakes would not refute this view.

The second is the question of how we acquire innate phobias. I am not aware of any plausible mechanism other than by natural selection, which is a multi-generational process of learning from what would be, at least in the case of a theory of mind, a fuzzy indirect set of second-order observables. Natural selection is, of course, a process that is explicitly modeled in our most successful machine-learning strategies.