"All conceivable interests of a debtor, even those that are future, nonpossessory, contingent, speculative, or derivative, lie within the scope of ยง 541." Bernstein v. Himel (In re Himel), 190 B.R. 59, 61 (Bankr. W.D. Pa. 1995). The nature of the estate's interest in property is determined by reference to state law.