Common General Knowledge

The common general knowledge is the knowledge a person skilled in the art is expected to possess.

While the construction of a patent is for the Court, like that of any other legal document, it is however to be done on the basis that the addressee is a man skilled in the art and the knowledge such a man is expected to possess is to be taken into consideration. [p. 563]

Justice Gauthier observed that the general statements made by the Supreme Court of Canada in Whirlpool and Sanofi must be read together with other classic comments that are still applicable. Classic comments were noted in the passage below.

[96] The very general statements made recently by the Supreme Court of Canada that [c]ommon general knowledge means knowledge generally known by persons skilled in the relevant art at the relevant time (Apotex Inc. v. Sanofi-Synthelabo Canada Inc., 2008 SCC 61, [2008] 3 S.C.R. 265 (Sanofi)) or that a posita is expected to be reasonably diligent in keeping up with advances in the field to which the patent relates and that their common knowledge undergoes continuous evolution and growth (Whirlpool, para. 74) must be read together with other classic comments that are still applicable.

[97] As noted in General Tire & Rubber Co. v. Firestone Tyre & Rubber Co. Ltd, [1972] RPC 457, [1971] FSR 417 (U.K.C.A.) (General Tire) at pp. 482-483 (of the RPC):

The common general knowledge imputed to such an addressee must, of course, be carefully distinguished from what in patent law is regarded as public knowledge. This distinction is well explained in Halsbury’s Law of England, Vol. 29, para. 63. As regards patent specifications it is the somewhat artificial (see per Lord Reid in the Technograph case [1971] F.S.R. 188 at 193) concept of patent law that each and every specification, of the last 50 years, however unlikely to be looked at and in whatever language written, is part of the relevant public knowledge if it is resting anywhere in the shelves of the Patent Office. On the other hand, common general knowledge is a different concept derived from a commonsense approach to the practical question of what would in fact be known to an appropriately skilled addressee — the sort of man, good at his job, that could be found in real life.

The two classes of documents which call for consideration in relation to common general knowledge in the instant case were individual patent specifications and widely read publications.

As to the former, it is clear that individual patent specifications and their contents do not normally form part of the relevant common general knowledge, though there may be specifications which are so well known amongst those versed in the art that upon evidence of that state of affairs they form part of such knowledge, and also there may occasionally be particular industries (such as that of colour photography) in which the evidence may show that all specifications form part of the relevant knowledge.

As regards scientific papers generally, it was said by Luxmoore, J. in British Acoustic Films (53 R.P.C. 221 at 250):

In my judgment it is not sufficient to prove common general knowledge that a particular disclosure is made in an article, or series of articles, in a scientific journal, no matter how wide the circulation of that journal may be, in the absence of any evidence that the disclosure is accepted generally by those who are engaged in the art to which the disclosure relates. A piece of particular knowledge as disclosed in a scientific paper does not become common general knowledge merely because it is widely read, and still less because it is widely circulated. Such a piece of knowledge only becomes general knowledge when it is generally known and accepted without question by the bulk of those who are engaged in the particular art; in other words, when it becomes part of their common stock of knowledge relating to the art.

And a little later, distinguishing between what has been written and what has been used, he said:

It is certainly difficult to appreciate how the use of something which has in fact never been used in a particular art can ever be held to be common general knowledge in the art.

Those passages have often been quoted, and there has not been cited to us any case in which they have been criticised. We accept them as correctly stating in general the law on this point, though reserving for further consideration whether the words accepted without question may not be putting the position rather high: for the purposes of this case we are disposed, without wishing to put forward any full definition, to substitute the words generally regarded as a good basis for further action.

[98] In Mahurkar v. Vas-Cath of Canada Ltd. (1988), 16 F.T.R. 48, 18 C.P.R. (3d) 417, Justice Barry Strayer noted, at para. 27:

In reviewing the prior art I have also been persuaded by counsel for the plaintiff that an objective test should be applied to determine whether the hypothetical skilled workman in the art could be reasonably assumed to have knowledge of such prior art. There appears to be adequate authority in the jurisprudence for such a test. No evidence was produced by the defendants to show that the ordinary skilled workman should be assumed to have been aware of all of this prior art. Frankly I find it difficult to believe that several of the items of prior art would have been present to the mind of the ordinary skilled workman in 1981.

[Emphasis added]

[99] Furthermore, as noted by Justice Karen Sharlow in Janssen-Ortho Inc. v. Novopharm Ltd., 2007 FCA 217, 366 N.R. 290, at para. 25 (citing factors developed by Justice Hughes in Janssen-Ortho Inc. v. Novopharm Ltd., 2006 FC 1234, 301 F.T.R. 166 (Janssen-Ortho (2006)):

Not all knowledge is found in print form. On the other hand, not all knowledge that has been written down becomes part of the knowledge that a person of ordinary skill in the art is expected to know or find.

[100] With respect to the proof required to establish common general knowledge, this passage from Simon Thorley et al., Terrell on the Law of Patents, 16^th ed. (London: Sweet & Maxwell, 2006) (Terrell), at 6-39 is relevant:

Proof of common knowledge is given by witnesses competent to speak upon the matter, who, to supplement their own recollections, may refer to standard works upon the subject which were published at the time and which were known to them. In order to establish whether something is common general knowledge, the first and most important step is to look at the sources from which the skilled addressee could acquire his information.

The publication at or before the relevant date of other documents such as patent specifications may be to some extent prima facie evidence tending to show that the statements contained in them were part of the common knowledge, but is far from complete proof, as the statements may well have been discredited or forgotten or merely ignored. Evidence may, however, be given to prove that such statements did become part of the common knowledge.

[Footnotes omitted.]

The common general knowledge undergoes continuous evolution and growth.

While the hypothetical ordinary worker is deemed to be uninventive as part of his fictional personality, he or she is thought to be reasonably diligent in keeping up with advances in the field to which the patent relates. The common knowledge of skilled workers undergoes continuous evolution and growth. The trial judge made a finding of fact that it would be unsafe to rely on Mr. Mellinger’s evidence because he had failed to keep up to date in this respect. [para. 74]

Common general knowledge means knowledge generally known by persons skilled in the relevant art at the relevant time. [para. 37]

This case illustrates that the relevant time depends on the issue at hand. For instance, for obviousness, the relevant time is the claim date, whereas for claim construction, the relevant time is the publication date.

[135] A distinction between the common general knowledge for the purposes of claim construction and for the purposes of assessing obviousness is the critical date. For claim construction, it is the date of publication (in this case, August 25, 2003). For obviousness, the critical date is the claim date (in this case, February 25, 2002, or May 30, 2002 for claims defining an absence of stiffening rods/members/inserts).

A problem statement in a Summary of the Invention section of a patent might be used as evidence of the common general knowledge.

[39] The appellant argues that in many cases, as in this instance, inventiveness lies in recognizing that a problem exists. The appellant recognized that the current production tank heating method was inefficient, and invented a solution to this problem. In the patent, the problem statement appears directly after a header that reads SUMMARY OF THE INVENTION and thus clearly was presented as part of the invention rather than as part of the background, the appellant argues. The Board thus based its rejection on an incorrect assumption that the inherent inefficient method of heating the tank with a separate heat source was part of the prior art and common general knowledge.

[40] While the Board did not cite any evidence other than the patent for the proposition that there was a known problem of inefficient heating in oil production storage tanks, it was reasonable for the Board to consider the information found under the SUMMARY OF THE INVENTION heading, to be part of the background knowledge which the skilled person would have. I agree with the respondent that it is an elevation of form over substance to say that because the problem which the invention sought to solve was presented under that heading, the matters described there were part of the invention and could not have been known to the skilled person.