What is the “possession” standard in written description requirement?

This page is an FAQ based on guidance from the Manual of Patent Examining Procedure. It is provided as guidance, with links to the ground truth sources. This is information only: it is not legal advice.

The “possession” standard is a key concept in the written description requirement. According to MPEP 2304.02(d):

“To satisfy the written description requirement, a patent specification must describe the claimed invention in sufficient detail that one skilled in the art can reasonably conclude that the inventor had possession of the claimed invention.”

This standard requires that the specification demonstrate that the inventor had conceptual possession of the full scope of the claimed invention at the time of filing. It’s not enough to merely describe the general idea; the description must be sufficiently detailed to show that the inventor had a complete and specific conception of the invention.