Substantive law creates rights; presumption of prospectivity prevents retroactive alteration of vested entitlements. Substantive law creates, defines and regulates rights and liabilities, whereas procedural law supplies the mechanism for enforcing them. Statutory rights are presumed prospective and remain governed by the law as it existed when proceedings began unless the new statute clearly intends retrospective operation. Procedural or declaratory provisions, lacking vested entitlements, may operate retrospectively. Consequently, changes affecting vested rights-such as accrued entitlements to interest-are not applied retroactively without unmistakable legislative intent.