What are the two criteria for subject matter eligibility?
First, the claimed invention must be in one of the four statutory categories. 35 U.S.C. 101 defines the four categories of invention that Congress deemed to be the appropriate subject matter of a patent: processes, machines, manufactures and compositions of matter.
Second, the claimed invention also must qualify as patent-eligible subject matter, i.e., the claim must not be directed to a judicial exception unless the claim as a whole includes additional limitations amounting to significantly more than the exception. The judicial exceptions (also called “judicially recognized exceptions” or simply “exceptions”) are subject matter that the courts have found to be outside of, or exceptions to, the four statutory categories of invention, and are limited to abstract ideas, laws of nature and natural phenomena (including products of nature).
The answer to this question can be found in chapter 2100 of the MPEP. This chapter covers patentability.
The answer is from the 9th Edition, Revision 08.2017. Depending on future changes to the MPEP, the question and answer may or may not be applicable in later Editions or revisions.
This question and answer comes from section 2106 of the MPEP. The following is a brief summary of section 2106.
2106 Patent Subject Matter Eligibility
This section discusses the two criteria for subject matter eligibility which are; that the claimed invention must be in one of the four statutory categories and that the claimed invention must also qualify as patent-eligible subject matter. It also covers details of the broadest reasonable interpretation (BRI) including that the BRI of the claim must be established prior to examining a claim for eligibility. Lastly, there is a summary of the patent subject matter eligibility analysis and a flowchart outlining the steps.