[3] The sufficiency of the disclosure, with any valid amendments made to it, is judged at the patent's claim date.
[5] If a person skilled in the art can arrive at the same results only through chance or further long experiments, the disclosure is insufficient and the patent is void.
[5] The disclosure must give skilled readers enough information for them to easily use the invention when the patent expires, and for them to try to improve on or experiment with it in the meanwhile.
[5] If a person skilled in the art would readily spot the mistake or omission and quickly correct it by using common general knowledge and the rest of the patent, but without "prolonged research, inquiry or experiment" or inventiveness, then this will not invalidate a patent.
[7] The mode must be the best one the inventor knows at the claim date, and must be well enough disclosed for other skilled workers to practice it without undue experiment.
This led one court to recently confine the doctrine to machines while admitting that "common sense and fair play" would extend this duty to all inventions.
[7][9] Some authors such as Professor Vaver argue that this revisionism seems wrong given prior case law and the Supreme Court of Canada's decision in Consolboard Inc. v. MacMillan Bloedel (Saskatchewan) Ltd. which recognized [7][10] that the Act's disclosure provision is badly drafted and cannot be read literally.
"[13] Since each claim is an independent grant of monopoly, one or more may be found invalid without necessarily affecting the validity of any other.
Predicting how a court will assess the technology and conflicting expert evidence on meaning and then figure out a claim's "true" meaning is close to soothsaying - or, as one court put it less succinctly, "an intracranial iterative process, involving multiple factors, including natural meaning, documentary context, technical considerations, commercial context, and business common sense.
[15] However, multiple claims covering all facets are allowed in the same patent if a "single inventive concept" links them.
A wrong decision by an applicant can cause severe problems and may even risk invalidation of the patent(s).
(2) Where it appears to a court that the omission or addition referred to in subsection (1) was an involuntary error and it is proved that the patentee is entitled to the remainder of his patent, the court shall render a judgment in accordance with the facts, and shall determine the costs, and the patent shall be held valid for that part of the invention described to which the patentee is so found to be entitled.Thus, the Act stipulates that the specifications and drawings should contain only what is needed to describe, disclose, and exemplify the inventions.
[23] Innocent errors in the specifications and drawings thus appear not to invalidate an entire patent.