One of the most frustrating expressions I came across in my college mathematics texts was “and, as would be obvious to the most casual observer…” I always thought to myself, “What? Obvious to you maybe.”

Later, I became exposed to a new kind of analysis that also used the word “obvious” – the non-obviousness test for patentability under 35 U.S.C. Sec. 103. This test seemed simple enough: Would a claimed invention have been obvious at the time it was made to a person of ordinary skill in the art? Since it was an objective analysis based on the differences between the prior art and the claimed invention, it seemed eminently more rationale than “obvious to the most casual observer” test. But, of course, its application was far from simple.

Starting in 1983, the Federal Circuit developed successively more objective refinements of the obviousness test, culminating in the teaching-suggestion-motivation (TSM) test. Under TSM, a patent claim could be found obvious based on a combination of prior art references only if a teaching, suggestion or motivation to combine those references was also in the prior art. While the objectivity of this test was laudable, its strict application lead to some perplexing results, for example, patents on such seemingly obvious inventions as crust-less peanut butter and jelly sandwiches or methods of swinging on toy swings. Even such casual observers as the Wall Street Journal and the New York Times began to take note.

So, in KSR Intl. Co. v. Teleflex Inc., the Supreme Court rejected the rigid TSM approach to obviousness. Although finding the TSM test to be a “helpful insight,” the Court held that it had been applied by the Federal Circuit in an overly formalistic manner inconsistent with prior precedents. Cautioning that courts must still conduct an explicit obviousness analysis, the Court explained that factors such as design needs, market demands, and “common sense” may provide sufficient reasons for combining prior art elements.

In the last few years, the latter factor, “common sense,” has received considerable attention since some feared that reliance on common sense could bring about widespread rulings of obviousness based on hindsight. Generally speaking, these concerns have not been realized – yet. While common sense has been used in certain obviousness arguments, its overall weight in the inquiry has been reasonably limited.

Courts have employed the common sense consideration for different uses. In Wyers v. Master Lock Co., the Federal Circuit found that common sense provided the motivation for combining the prior art even where expert testimony was not presented on one of the prior art references. The Court had no problem with such logic as results were predictable.

Similarly, in Sundance, Inc. v. Demonte Fabricating Ltd., the Court found retractable tarpaulins used to cover truck trailers to be a simple technology and stated that no expert testimony was needed to apply the disclosure of the prior art to the asserted patent. Common sense here was akin to taking judicial notice of the combination of elements.

Common sense has also been used to supply a missing claim element. In Perfect Web Techs., Inc. v. InfoUSA, Inc., the patented technology involved a four-step method of handling and processing bulk e-mail where the first three steps were disclosed in the prior art. The last step involved repeating the earlier steps until a specified number of e-mails have been successfully received. The Court found the last step of repeating a known procedure until achieving success to be simply a matter of common sense.

However, where possible solutions to a problem were numerous, as in Rolls-Royce, PLC v. United Techs. Corp., common sense reasoning did not make a particular solution obvious to try, and the Federal Circuit affirmed a holding that claims to a fan blade used on a jet engine were not obvious.

Similarly, blind reliance on common sense without sufficient reasoning has been found insufficient. In TriMed Inc. v. Stryker Corp., the Federal Circuit reversed a grant of summary judgment where the district court provided only conclusory reasoning that the prior art combination was a common sense solution. The Federal Circuit admonished the lower court: “saying that an invention is a logical, common sense solution to a known problem does not make it so.” In other words, simply saying something would have been obvious to the most casual observer is not a particularly helpful or convincing step in a proof.

MIlbank associate Nate Browand contributed to this column.

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