Common General Knowledge

1Common general knowledge is a part of the mental requirement of a person skilled in the art. It is the mental tools of the trade of a person skilled in the art. (SmithKline Beecham Plc v Apotex Europe [2005] FSR 23, para 96.) It is the technical background of the notional man in the art against which the prior art must be considered. (Raychem Corpn’s Patent (1998) RPC 31, p 40.) The proof of common knowledge is given by expert witnesses. (See British Celanese Ltd v Courtaulds Ltd (1933) 50 RPC 63, p 90; Bühler AG v Satake UK Ltd (1997) RPC 232, p 236.) In construing patents, the court will have to put itself in the position of a skilled addressee at the time the specification was published and look at the patent from the standards of the common general knowledge of such person. Common general knowledge refers to the ‘common knowledge in art and science to which the alleged invention relates, so as to be known to duly qualified persons engaged in that art or science’. (British Thomson-Houston Co Ltd v Stonebridge Electrical Co Ltd (1916) 33 RPC 166, p 171.) It is not limited to the material the person skilled in the art has memorised and has at the front of his mind. It also includes ‘all that material in the field he is working in, which he knows exists, which he would refer to as a matter of course if he cannot remember it, and which he understands is generally regarded as sufficiently reliable to use as a foundation for further work or to help understand the pleaded prior art’. (Raychem Corpn’s Patent (1998) RPC 31, p 40.)

2The knowledge should be of a general nature. It will not suffice to show that a matter was known to some but not to others, and in particular, it will not be good enough to show that knowledge, or even a prejudice ‘was confined to one or a limited class of suggested exemplars of the skilled man’. (Union Carbide Corpn v BP Chemicals Ltd (1998) RPC 1, p 16.) A concept that is well-known to some will not be a part of the common general knowledge if it was not known to the bulk of those skilled in the art. (Beloit Technologies Inc v Valmet Paper Machinery Inc (1997) RPC 489.) The person skilled in the art cannot be expected to find such knowledge ‘buried in acknowledgements of the prior art’. (Halliburton Energy Services Inc v Smith International (North Sea) Ltd [2006] EWCA Civ 1715, para 67 (CA).) In other words: (Raychem Corpn’s Patent (1998) RPC 31, p 40, per Laddie J.)

This does not mean that everything on the shelf which is capable of being referred to without difficulty is common general knowledge nor does it mean that every word in a common text book is either. In the case of standard textbooks, it is likely that all or most of the main text will be common general knowledge. In many cases common general knowledge will include or be reflected in readily available trade literature which a man in the art would be expected to have at his elbow and regard as basic reliable information.

3Common general knowledge must be distinguished from public knowledge as observed in General Tire & Rubber Co v The Firestone Tyre and Rubber Co Ltd, by Sachs LJ: ([1971] FSR 417, p 439.)

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 Laws of England, vol 29, para 63. As regards patent specifications it is the somewhat artificial (see per Lord Reid in the Technograph case [1971] FSR 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.

4The difficulty in demarcating the realm of common knowledge and that of specialised knowledge is discussed in Beloit Technologies Inc v Valmet Paper Machinery Inc, where Aldous LJ, observed: ((1997) RPC 489, p 494 (CA).)

It has never been easy to differentiate between common general knowledge and that which is known by some. It has become particularly difficult with the modern ability to circulate and retrieve information. Employees of some companies, with the use of libraries and patent departments, will become aware of information soon after it is published in a whole variety of documents; whereas others, without such advantages, may never do so until that information is accepted generally and put into practice. The notional skilled addressee is the ordinary man who may not have the advantages that some employees of large companies may have. The information in a patent specification is addressed to such a man and must contain sufficient details for him to understand and apply the invention. It will only lack an inventive step if it is obvious to such a man.

It follows that evidence that a fact is known or even well-known to a witness does not establish that that fact forms part of the common general knowledge. Neither does it follow that it will form part of the common general knowledge if it is recorded in a document. As stated by the Court of Appeal in General Tire & Rubber Co v Firestone Tyre & Rubber Co Ltd [1972] RPC 457, at page 482, line 33:

‘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 RPC 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’.’

Knowledge of regulatory requirements will not be imputed to be a part of the common general knowledge for the purpose of determining obviousness. (Ivax Pharmaceuticals UK Ltd v Akzo Nobel NV [2006] EWHC 1089 (CH).)