Law - Statutory Class

U.S. patent law requires that patentable inventions fall within one of five classes of statutory inventions. The classes of inventions are (1) a process, (2) a machine, (3) an (article of) manufacture, (4) a composition of matter and (5) an improvement of an invention in one of the other four classes (35 U.S.C. 101). Inventions in classes 2, 3, and 4 are sometimes referred to as products.

A statutory "process" can be (1) a method of operation of a machine or a method of operation on (or using) a composition of matter or on an article of manufacture or (2) a process of making something. Inventions that are processes are also referred to as methods, techniques, or arts. The statutory class process also includes a new use of a known process, machine, manufacture, or composition of matter. Examples of process inventions are as follows: a method of operation of a computer, a method of using a microorganism, a method of making a product, a method of playing a game, etcetera.

A statutory "machine" is an apparatus that performs some function. Inventions that are machines are also referred to as apparatus, devices or systems. Examples of machines are as follows: a general-purpose computer programmed to perform a certain operation, an apparatus for carrying out a certain process, a carburetor, etcetera.

A statutory "article of manufacture" is a manufactured product. There is no clear distinction between a machine and an article of manufacture in the law. Inventions that are articles of manufacture are also referred to as articles or manufactures. Examples of articles of manufacture are as follows: a product made by a particular process, a capacitor, a child-resistant package, etcetera.

A statutory "composition of matter" is a combination of chemical components. Inventions that are compositions of matter are also referred to as compositions. There is often no clear distinction between an article of manufacture and some types of a composition of matter. Examples of compositions of matter are as follows: a purified protein, a polymer, an alloy, a mixture, a solution, etcetera.

The position of the USPTO on this issue is described in the following section(s) of the Manual of Patent Examining Procedures (MPEP):

MPEP 706.03(a) - Rejections under 35 U.S.C. 101
MPEP 2105 - Patentable Subject Matter - Living Subject Matter
MPEP 2106 - Patentable Subject Matter - Computer-Implemented Inventions

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