(This post grew out of an old conversation with Wei Dai.)
Imagine a person sitting in a room, communicating with the outside world through a terminal. Further imagine that the person knows some secret fact (e.g. that the Moon landings were a hoax), but is absolutely committed to never revealing their knowledge of it in any way.
Can you, by observing the input-output behavior of the system, distinguish it from a person who doesn't know the secret, or knows some other secret instead?
Clearly the only reasonable answer is "no, not in general".
Now imagine a person in the same situation, claiming to possess some mental skill that's hard for you to verify (e.g. visualizing four-dimensional objects in their mind's eye). Can you, by observing the input-output behavior, distinguish it from someone who is lying about having the skill, but has a good grasp of four-dimensional math otherwise?
Again, clearly, the only reasonable answer is "not in general".
Now imagine a sealed box that behaves exactly like a human, dutifully saying things like "I'm conscious", "I experience red" and so on. Moreover, you know from trustworthy sources that the box was built by scanning a human brain, and then optimizing the resulting program to use less CPU and memory (preserving the same input-output behavior). Would you be willing to trust that the box is in fact conscious, and has the same internal experiences as the human brain it was created from?
A philosopher believing in computationalism would emphatically say yes. But considering the examples above, I would say I'm not sure! Not at all!
But you could not have used it to make a point about links between meaning, detectabiity, and falsehood.
The implicit argument is that meaning/communication is not restricted to literal truth.
What would happen is that you are changing the hypothesis. Originally, you stipulated an invisible unicvorn as undetectable in any possible way, in relation to which I agreed that one could use an armchair argument like occam's razor against their existence. Now you imply that they possible could be detected, in which case I withdraw my original claim, because if something could be detected, then armchair arguments are not appropriate.
No, but I can use it to make a point about how low your bar for meaningfulness is. Does that not count for some reason? I asked you before to propose a meaningless statement of your own. Do none exist? Are none of them grammatically correct?
???
Yes, the unicorns don't have to be undetectable be definition. They're just undetectable by all methods that I'm ... (read more)