The framework has not changed since 1966
Section 103 bars a patent where the differences between the claimed invention and the prior art are such that the invention as a whole would have been obvious to a person of ordinary skill in the art at the time. Graham v. John Deere Co. set out the factual inquiries that structure the question, and they still do:
- the scope and content of the prior art;
- the differences between the prior art and the claims at issue;
- the level of ordinary skill in the art; and
- objective evidence of nonobviousness, where present.
Obviousness is a legal conclusion resting on those findings of fact. That structure matters in practice: an obviousness rejection that never makes a finding on one of the inquiries is incomplete, and saying so is often more productive than arguing the merits of the combination.
What KSR changed, and what it did not
Before KSR Int'l Co. v. Teleflex Inc., the teaching-suggestion-motivation test was frequently applied as a rigid requirement for an explicit prior-art teaching to combine. KSR rejected that rigidity, holding that the analysis is expansive and flexible, that common sense has a place in it, and that a combination of familiar elements according to known methods is likely obvious when it yields predictable results.
What KSR did not do is remove the requirement of an articulated reason. The Court's own language requires some articulated reasoning with rational underpinning to support the legal conclusion. So the post-KSR question is not whether the examiner found an explicit teaching to combine, but whether the reason given is articulated and rationally supported. A rejection resting on nothing more than the assertion that a combination would have been obvious remains deficient after KSR — not because of the teaching-suggestion-motivation test, but because of the reasoning requirement KSR itself imposed.
How a rejection is built
The MPEP walks examiners through this in a sequence worth knowing, because a response is more effective when aimed at the right step.
- § 2141 is the operative examination guideline, tying the Graham inquiries to the reasoning requirement.
- § 2142 covers the legal concept of a prima facie case: what the Office must establish before the burden shifts to the applicant.
- § 2143 collects the recognized rationales — combining prior art elements with predictable results, simple substitution, use of a known technique to improve a similar device, obvious to try, and others — each with the findings that rationale requires. Identifying which rationale the examiner actually relies on, and then testing whether its specific predicates were established, is usually the most efficient traversal available.
- § 2144 addresses supporting a rejection, including reliance on the examiner's own technical reasoning.
- § 2145 covers rebuttal: how the Office is to treat the applicant's arguments and evidence once the burden has shifted.
Where responses succeed
Attacking the rationale's predicates rather than the conclusion. A reasonable expectation of success is required, and the predictability of the art is a factual matter. In an unpredictable art, the assertion that a substitution would have been routine is a finding that has to be supported.
Objective evidence, when it is genuinely available. Commercial success, long-felt need, failure of others and unexpected results are part of the Graham framework, not an afterthought, and must be considered when presented. The recurring weakness is nexus: the evidence has to be tied to what is claimed, and establishing that link is the applicant's burden.
Reading the reference as a whole. A reference that teaches away, or whose modification would render it unsatisfactory for its intended purpose, undercuts a combination rationale in a way that a general argument about the differences between the references does not.