The teaching-suggestion-motivation (TSM) test is currently used by the United States Court of Appeals for the Federal Circuit to determine if two or more prior art references can legitimately be combined2 during the § 103 obviousness inquiry.3 The TSM test enjoys a long, rich history predating the Federal Circuit, and even its predecessor the United States Court of Customs and Patent Appeals (CCPA). With the changing conceptions of “invention/obviousness,” originally coined “invention” and later codified as “obviousness,” the TSM test coevolved.4 The primary benefit of this co-evolution is a test for obviousness that operates in a manner consistent with the principles of Graham while at the same time providing a pragmatic method which could be used in proceedings of the patent office and courts alike. 5
The TSM test was identified early-on as one method of evaluating the legitimacy of combining multiple references.6 The other important recurring concepts relevant to “invention/obviousness” were also identified surprisingly early; most before 1900. 7
2 The TSM test is not the only test that is available to determine whether a claimed invention is obvious, just the one used when two or more references need to be combined to show the claimed invention. A claimed invention may be an obvious extension to the prior art. Only a single reference and a reasoned argument of why the extension is obvious is necessary. The TSM test does not play a role, because there is no combination of multiple references, and therefore no need for a motivation to combine. See Orthopedic Equipment Company v. All Orthopedic Appliances, 707 F.2d 1376, 1382 (Fed. Cir. 1983).
In other instances, the “combination” may not be a combination at all, but merely a collection of parts well-known in the art and each performing their common function without any significant interaction. See Anderson's-Black Rock v. Pavement Salvage, 396 U.S. 57 (1969). Before the Patent Act of 1952, this grounds for rejection was termed “aggregation.” See In re Gustafson, 331 F.2d 905, 908-910 (CCPA 1964) for a discussion by Judge Rich of obviousness as the replacement for aggregation. The determination of whether a claimed invention is merely an aggregation is a prelude to applying the TSM test, because there is no requirement for stating a motivation to combine when there is no real combination in the claimed invention.
3 See for example Ashland Oil, Inc. v. Delta Resins & Refractories, Inc., 776 F.2d 281, 297 n. 24, (Fed.Cir.1985) (stating that the knowledge of one skilled in the art may provide the "teaching, suggestion, or inference" to combine references), cert. denied, 475 U.S. 1017, (1986). In re Dembiczak, 175 F.3d 994, 999, (Fed.Cir.1999) (“We have noted that evidence of a suggestion, teaching, or motivation to combine may flow from the prior art references themselves, the knowledge of one of ordinary skill in the art, or, in some cases, from the nature of the problem to be solved”) citing Pro– Mold & Tool Co. v. Great Lakes Plastics, Inc., 75 F.3d 1568, 1573, (Fed.Cir.1996), Para– Ordnance Mfg. v. SGS Importers Intern., Inc., 73 F.3d 1085, 1088, (Fed.Cir.1995).
4 The Patent Act of 1952 codified the judicially created requirement of “invention.” Because obviousness was meant to act as a more precise formulation of “invention,” it is reasonable for purposes of this paper to equate the two.
5 In re Huang, 100 F.3d 135, 138 (Fed.Cir.1996) (“The ultimate determination as to whether or not an invention is obvious is a legal conclusion based on underlying factual inquiries including: (1) the scope and content of the prior art; (2) the level of ordinary skill in the art; (3) the differences between the claimed invention and the prior art; and (4) objective evidence of nonobviousness.”) citing Graham v. John Deere Co., 383 U.S. 1, 17– 18, (1966).
6 Topliff v. Topliff, 145 U. S. 156, 161, (1892) (“Their device evidently approached very near the idea of an equalizer; but this idea did not apparently dawn upon them, nor was there anything in their patent which would have suggested it to a mechanic of ordinary intelligence, unless he were examining it for that purpose.”) Emphasis added.
Discussed extensively below.