I asked you before to propose a meaningless statement of your own.
And what I said before is that a well-formed sentence can robustly be said to be meaningful if it embeds a contradiction, like "colourless green", or category error, like "sleeping idea".
So, what you're saying, is that you don't know if "ghost unicorns" exist? Why would Occam's razor not apply here? How would you evaluate the likelihood that they exist?
Very low finite rather than infinitessimal or zero.
I don't see how this is helping. You have a chain of reasoning that starts with your not knowing something, how to detect robot pain, and ends with your knowing something: that robots don't feel pain. I don't see how that can be valid.
category error, like "sleeping idea"
Obviously I agree this is meaningless, but I disagree about the reasoning. A long time ago I asked you to prove that "bitter purple" (or something) was a category error, and your answer was very underwhelming.
I say that "sleeping idea" is meaningless, because I don't have a procedure for deciding if an idea is sleeping or not. However, we could easily agree on such procedures. For example we could say that only animals can sleep and for every idea, "is this idea sleeping" is ans...
(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!