Claim only what you have taught

The trade at the center of a patent

A claim is the statement that defines what you own. The specification is what you teach. The two are tied together. The Supreme Court said in Amgen that the specification "must enable a person skilled in the art to make and use the entire class", and it gave the rule in one line: "The more one claims, the more one must enable" (Amgen v. Sanofi). A person skilled in the art is a working practitioner in the field.

Morse, told correctly

Samuel Morse claimed electromagnetism "however developed". The Court said he claimed "a manner and process which he has not described and indeed had not invented" (O'Reilly v. Morse).

The story is often told wrong. Morse did not lose his patent. Only claim 8 fell, because separate claims protected him (O'Reilly v. Morse). In our judgment, that is the second lesson of the case: claims of different widths mean one overreach does not take down the rest.

How broad is too broad

In Incandescent Lamp, a claim to every fibrous material failed, and Edison's search through over 6,000 vegetable growths was what defeated it. The Court allowed that a genus, meaning a whole class of things, "might not be too broad" with "a quality common to them all" (Consolidated Electric Light v. McKeesport). So broadening needs a reason: a property that your data shows the members share.

The other side of the line matters too. An inventor need not reach "the highest degree of perfection" if the patent "points out some practicable way" (The Telephone Cases). The Wright brothers' patent said expressly that their invention was not limited to the construction it showed (US 821,393).

Two separate requirements

Written description and enablement are separate (Teva v. Lilly). Written description shows possession, meaning you actually had the invention you claim (MPEP § 2163). Enablement means a skilled reader can make and use it without undue experimentation, assessed under Wands (MPEP § 2164).

A working habit

WIPO's drafting manual gives the practical rule: disclose "a working embodiment", a concrete version that works, and help the inventor consider alternatives, because inventors "often work to solve a very specific problem" (WIPO Patent Drafting Manual). Before you widen a claim, write down the variations you can actually teach.