ELI5 What exactly is the mind-body problem

ELI5: What exactly is the mind-body problem? : explainlikeimfive

So here's the problem: it is now apparent that things inside your mind aren't necessarily the same thing as the actual physical thing stimulating your senses, because not only do we have slightly different sensory experiences, but the very things inside people's minds are dependent on every other thing that's also inside their mind.

So now there seems to be a distinction between the experience of something and the actual physical thing.

The experience is completely dependent on a subjective observer. Hence, the qualitative difference between physical, shared-experience-objects, and mental, subjective-experience objects.