As long as we can agree that whether someone cares about X is an empirically discoverable fact, then there seem to be two currently-possible methods of finding out what that is: introspection and viewing their actions (“revealed preference”).
There is no amount of evidence about facts external to a person that could possibly bear on whether they care about X. You might change whether they care about X by presenting external input, but that’s a rather different thing.
As long as we can agree that whether someone cares about X is an empirically discoverable fact, then there seem to be two currently-possible methods of finding out what that is: introspection and viewing their actions (“revealed preference”).
There is no amount of evidence about facts external to a person that could possibly bear on whether they care about X. You might change whether they care about X by presenting external input, but that’s a rather different thing.