The two think they have different models of the world, but they have no difference with respect to what they expect will happen to them.
You can define a thing based on any criteria you like. It simply has to allow your expectations to agree with reality in order for it to be true.
One says “it is sound because it vibrates regardless of whether anyone hears it.” This person believes that sound is the vibrations.
The other says “it is not sound because it is never processed in a mind.” This person does not deny that the vibrations exist, he simply believes it isn’t sound until someone hears it.
These two have different definitions of “sound”, but within their definitions both allow expectations that are completely consistent with reality. The point is to make sure your beliefs “pay rent”—that they allow you to have expectations that match up with reality. If the second person had the same belief of what sound was as the first (i.e. vibrations in the air), yet also believed that vibrations in the air do not occur when there is nobody to hear them, that belief would not pay rent. When they recorded the sound with nobody around he would expect there to be nothing at all on the tape, yet there would be something on the tape. The only way to resolve this is to adjust your belief after the fact, which means your belief couldn’t pay its rent.
I think that may have been the point:
You can define a thing based on any criteria you like. It simply has to allow your expectations to agree with reality in order for it to be true.
One says “it is sound because it vibrates regardless of whether anyone hears it.” This person believes that sound is the vibrations.
The other says “it is not sound because it is never processed in a mind.” This person does not deny that the vibrations exist, he simply believes it isn’t sound until someone hears it.
These two have different definitions of “sound”, but within their definitions both allow expectations that are completely consistent with reality. The point is to make sure your beliefs “pay rent”—that they allow you to have expectations that match up with reality. If the second person had the same belief of what sound was as the first (i.e. vibrations in the air), yet also believed that vibrations in the air do not occur when there is nobody to hear them, that belief would not pay rent. When they recorded the sound with nobody around he would expect there to be nothing at all on the tape, yet there would be something on the tape. The only way to resolve this is to adjust your belief after the fact, which means your belief couldn’t pay its rent.