[Isinlor]

I use the same standard of knowing as I do for qualia in general. I listen to what other people report.

> there's a difference between receiving input from someone else's sensors and experiencing their qualia.

There can not be clear difference if you are not able to even fully separate two different personalities.

If distinction between personalities is fluid, then distinction between personalities qualia also has to be fluid.

[lisper]

But that's exactly what I'm asking: what does a report of shared qualia actually look like?

> If distinction between personalities is fluid

But it isn't. It might be vague but it isn't fluid. If two personalities are distinct then they remain distinct. It might be difficult to decide whether two different kinds of behavior are manifestations of two different personalities, or the same personality behaving differently from one moment to the next. But whatever criterion you apply, the situation is not going to change from one moment to the next. This is one of the defining characteristics of personalities. It is what allows you to say that a person is the same person as they were yesterday, despite their behavior today being different in some respects from what it was yesterday.

[Isinlor]

There can be one personality that can be split into two personalities. People with multiple personality disorders are not born with the disorder. The same with people whose corpus callosum is severed. It is fluid. The amount of damage to the brain will determine how distinct the personalities will be. If you could transplant brain it possible that one personality could create two fully distinct personalities. The process could be in principle also reverted back again leading to one personality.

Additionally, the process of separating parts of a brain is also continuous in time. People could be experiencing qualia when then brain is being damaged and the process could take long enough for them to register the states in between.

With regard to reports, here:

> He also reported to have grabbed his wife with his left hand and shaken her violently, at which point his right hand came to her aid and grabbed the aggressive left hand.

And here: https://youtu.be/N1Mac4FeKXg?t=124

With regard to definition of personalities - definitions created for an average case are often not sufficient to describe the reality. Quantum physics is a perfect example how reality can break old definitions.

[lisper]

> He also reported to have grabbed his wife with his left hand and shaken her violently, at which point his right hand came to her aid and grabbed the aggressive left hand.

I see that as evidence of two consciousnesses/personalities sharing one body (i.e. one set of I/O devices), not two personalities sharing qualia.