Simplify the following text for a Grade 8 native English-speaking person.
Original: The mind-body problem , i.e. the relationship of the mind to the body , is commonly seen as the central issue in philosophy of mind , although there are other issues concerning the nature of the mind that do not involve its relation to the physical body .
Simplified: The mind-body problem , i.e. the relationship of the mind to the body , is commonly seen as the central issue in philosophy of mind , although there are other issues that have to do with the nature of the mind that do not involve its relation to the real ( solid ) body .