A person, John has a brain disease. John has a double personality. Each personality( including john ` s personality) can occupy the body when the other two personality are not. Suppose we name the two other personality Jack, and Jeff. In a 12 hour day, John occupy the body for 4 hours, Jack occupy the body for 4 hours, and Jeff occupy the body for 4 hours.

Question:

John is legally bounded to do X. Is Jack, and Jeff legally bounded as well?
Suppose John signs contract to do X, and he is legally committed for "John ` s body to do X", then it seems Jeff, and Jack also have to do X if they occupy the same body. It seems that John `s body must be the legal property of John for John to sign the contract. Is "John` s body" a legal property of John? By symmetry of the situation, either all personality has legal property over John ` s body, or all don` t. There are two cases. Suppose all three personal owns John ` s body, then one personal can sell the body, and the other don` t. This cause problems for the buyer. On the other hand, if none of the personal has legal right over John ` s body, then they cannot sign any contract related to john ` s body. What do you think?