What is Abstraction Principle?

Legal Definition
The abstraction principle or Abstraktionsprinzip is a legal term in German law relating to the law of obligations (Schuldrecht) and property law (Eigentumsrecht). Although no express reference to it is made in the German civil law code (BGB), the concept of "abstracting" a personal obligation to pay or exchange goods or legal rights (e.g. through contract) from the transfer of proprietary title of goods or legal rights is fundamental to German private law.
-- Wikipedia
Legal Definition
A credit rule that stipulates a credit is not affected by its underlying agreement or contract. This is also called the autonomy principle