I have recently been involved in a matter involving the question of inventive step. As I briefly set out in a previous post, in order to be patentable, an invention must involve an inventive step. In Australia, this means that, at the priority date, the invention must not be obvious to a person skilled in the art in the light of the available prior art. I am sure I will be posting something about "prior art" in the future.
Finding a skilled person is easy enough if the relevant priority date is recent. However, it is often the case that the priority date is 10 or more years old. It can therefore be very difficult to find the right person and for that person to recall his or her state of mind 10 years ago.
The skilled person must be one who is not overly qualified, but who has the knowledge that could reasonably be expected to have been that of a technician. I use the word "technician" loosely, since the necessary qualifications and experience of the nominal skilled person will depend on the subject matter of the patent.
Anyway, having found that often elusive representative of the skilled person, it is then necessary to set a questionnaire for such a person. The questionnaire must not disclose any aspect of the invention, since the answers will be tainted with "hindsight". For those curious, the relevant case is Aktiebolaget Hassle v Alphapharm Pty Limited  HCA 59 (12 December 2002. The case is worth reading as it does manage to unravel some of the complexities of the inventive step requirement of our Patents Act.
While interesting, the whole exercise appears a little farcical to me. After all, how can it possibly be determined, on written evidence, that the nominal skilled person did not obtain some inkling of the invention? I would be interested in receiving comments from my foreign readers regarding the treatment of witnesses representative of the skilled person in the determination of obviousness.
In any event, Australian practitioners should be careful when using "object" clauses in a specification, where those clauses provide a guideline for such a questionnaire. For example, if the relevant claim were directed to an invention of a lightbulb filled with an inert gas, it may not be in client's best interest to include, by way of background: "An object of the invention is to prevent oxygen coming into contact with a lightbulb element." With such an object clause it would be legitimate to ask the skilled person: "How would you prevent oxygen from coming into contact with a lightbulb element?" (OK, so a silly example, but you know what I mean).