To be patentable, an invention must not be obvious. The requirement of non-obviousness is a natural corollary of the concept of “invention”, ¹ since the word “invention” itself implies a degree of “inventive ingenuity”.² Something is obvious if it is not inventive. Thus, patents cannot be granted to the obvious.

In other words, “obviousness is an attack on a patent based on its lack of inventiveness. The attacker, says, in effect, 'Any fool could have done that.'”³

Prior to 1996, the Patent Act in Canada did not expressly require non-obviousness. Nonetheless, courts developed a threshold for obviousness to give meaning to the term “invention”. For patents filed on or after October 1, 1989,⁴ the Patent Act expressly requires that an invention be non-obvious:

28.3 The subject-matter defined by a claim in an application for a patent in Canada must be subject-matter that would not have been obvious on the claim date to a person skilled in the art or science to which it pertains, having regard to

(a) information disclosed more than one year before the filing date by the applicant, or by a person who obtained knowledge, directly or indirectly, from the applicant in such a manner that the information became available to the public in Canada or elsewhere; and

(b) information disclosed before the claim date by a person not mentioned in paragraph (a) in such a manner that the information became available to the public in Canada or elsewhere.⁵

The post-1996 statutory language, however, continued to leave the term “obvious” undefined. As such, the amendments to the Patent Act did not change the law regarding obviousness.⁶ It merely codified what was already the law.

The most definitive statement in Canada on the requirement of obviousness is found in Apotex Inc v Sanofi‑Synthelabo Canada Inc,⁷ where Rothstein J. of the Supreme Court adopted a four-step approach developed in the UK:⁸

1. 1. Identify the notional “person skilled in the art”;
   2. Identify the relevant common general knowledge of that person;
2. Identify the inventive concept of the claim in question or if that cannot readily be done, construe it;
3. Identify what, if any, differences exist between the matter cited as forming part of the “state of the art” and the inventive concept of the claim or the claim as construed;
4. Viewed without any knowledge of the alleged invention as claimed, do those differences constitute steps which would have been obvious to the person skilled in the art or do they require any degree of invention?⁹

See also: POSITA

The person skilled in the art (sometimes referred to as a person of ordinary skill in the art or a person having ordinary skill in the art) is a hypothetical person versed in the field of the invention to which the patent is addressed.¹⁰

This hypothetical person was colourfully described in the context of the obviousness analysis by Hugessen J.A. in Beloit Canada Ltd v Valmet Oy:

The classical touchstone for obviousness is the technician skilled in the art but having no scintilla of inventiveness or imagination; a paragon of deduction and dexterity, wholly devoid of intuition; a triumph of the left hemisphere over the right. The question to be asked is whether this mythical creature (the man in the Clapham omnibus of patent law) would, in the light of the state of the art and of common general knowledge as at the claimed date of invention, have come directly and without difficulty to the solution taught by the patent. It is a very difficult test to satisfy.¹¹

Despite the label, the skilled person or technician need not be thought of as a single individual. It may also be a “composite of scientists, researchers and technicians bringing their combined expertise to bear on the problem at hand”.¹² This person or team, however, is not omnipotent. Rather, the skilled person is “ordinary”,¹³ “unimaginative”,¹⁴ “devoid of intuiton”,¹⁵ and “middle of her class”.¹⁶

See also: Common General Knowledge

The person of ordinary skill is also assumed to have some common general knowledge in the field of the invention.¹⁷ Furthermore, he or she “is thought to be reasonably diligent in keeping up with advances in the field to which the patent relates” and their common knowledge “undergoes continuous evolution and growth”.¹⁸

It is important to note, however, that not all “public knowledge” can be imputed to the skilled person. Whereas public knowledge may include everything that has been published and available in some form (including all published patent specifications), common general knowledge includes only information that can be found by a “reasonably diligent search”.¹⁹ Public knowledge only becomes common general knowledge “when it is generally regarded as a good basis for further action by the bulk of those who are engaged in the particular art”.²⁰

It has been held, for instance, that individual patent specifications do not necessarily form a part of the common general knowledge unless they are well known.²¹ On the other hand, common general knowledge can include things that are not written down.²² In light of modern information technology, the distinction between public knowledge and common general knowledge may become moot.²³

In patent trials, courts will generally hear testimony from expert witnesses in order to place themselves in the shoes of the person of ordinary skill in the art.²⁴ However, such witnesses are often in the paradoxical position of testifying as “ordinary” persons in their field despite the fact that they are usually highly qualified experts with accomplished careers and lengthy resumes. As a result, courts have cautioned against relying too heavily on statements by “overqualified” experts.²⁵

The words of Hugessen J.A. should continue to be heeded:

Every invention is obvious after it has been made, and to no one more so than an expert in the field. Where the expert has been hired for the purpose of testifying, his infallible hindsight is even more suspect. It is so easy, once the teaching of a patent is known, to say, “I could have done that”; before the assertion can be given any weight, one must have a satisfactory answer to the question, “Why didn't you?”²⁶

See also: claim construction

The last step of the Sanofi inquiry requires courts to look for a “degree of invention”.²⁷ If there is no degree of invention, then the patent as claimed is invalid due to obviousness. In many respects, the inquiry into inventiveness is at the heart of patent law. Patents are granted to “inventive solutions to practical problems”.²⁸ The degree of inventiveness required should be sufficiently high to justify a state-enforced monopoly.²⁹

The structure laid out by the Supreme Court in Sanofi has not made it any easier to answer the question of what degree of inventiveness is actually required. Courts must still ask whether there was an “inventive step” made by the patentee. Only a “scintilla” of inventiveness is necessary to meet the threshold.³⁰ What is meant by a “scintilla of inventiveness” has proven somewhat difficult to pin down.

Over the years, courts have developed numerous tests and proposed numerous factors to evaluate inventiveness. In Janssen-Ortho Inc v Novopharm Ltd, Hughes J. surveyed the jurisprudence from the United Kingdom, the United States, and Canada, arriving at a non-exhaustive list of factors that may be used to objectively evaluate the obviousness of a claimed invention.³¹ These factors were generally approved by Sharlow J.A. on appeal.³² While the Supreme Court of Canada declined to weigh in on these factors,³³ its later decision in Sanofi is not inconsistent with the Janssen-Ortho approach.³⁴

In addition to the steps listed in Sanofi, primary factors that may be used in determining obviousness include the climate in the relevant field, motivation, and effort and time spent on the alleged invention. Secondary factors may include commercial success and meritorious awards.³⁵

The climate in the relevant field refers to the general state of the art, and “includes not only knowledge and information but also attitudes, trends, prejudices and expectations.”³⁶ If it can be established that the state of the art in the field was generally biased against or taught away from the claimed invention, the invention may be non-obvious.³⁷ A discovery that is unexpected or surprising to persons skilled in the art may meet the required inventive step.³⁸