  in united states patent law, utility is a patentability requirement.u.s. const., art. i, Â§8, cl. 8 (congress shall have the power "to promote the progress of science and useful arts..." (emphasis not in original)); 35 u.s.c. Â§ 101 (2008) ("whoever invents or discovers any new and useful process, machine, manufacture or composition of matter...may obtain a patent...." (emphasis not in original) as provided by , an invention is "useful" if it provides some identifiable benefit and is capable of use.bedford v. hunt, 3 f. cas. 37 (c.c. mass. 1817)("the law...does not look to the degree of utility; it simply requires that it shall be capable of use....") the majority of inventions are usually not challenged as lacking utility, but the doctrine prevents the patenting of fantastic or hypothetical devices such as perpetual motion machines. the patent examiners guidelines require that a patent application expresses a specific, credible, and substantial utility.see brenner v. manson, 383 u.s. 519 (1966); uspto, utility examination guidelines, 66 fed. reg. 1092, 1098 (jan. 5, 2001) available at http://www.uspto.gov/web/offices/com/sol/notices/utilexmguide.pdf rejection by an examiner usually requires documentary evidence establishing a prima facie showing that there is no specific, substantial, and credible utility. european patent law does not consider utility as a patentability criterion.in this respect, decision t 388/04 of march 22, 2006 of the boards of appeal of the european patent office has made it clear that "subject-matter or activities may be excluded from patentability under  even where they have practical utility" (headnote iii.), thus ruling out the utility of an invention as a decisive patentability criterion. instead, it requires that to be patentable an invention must have industrial applicability.under the european patent convention, see for instance . == utility criterion == in considering the requirement of utility for patents, there are three main factors to review: operability of the invention, a beneficial use of the invention, and practical use of the invention. ===operability=== the importance of operability as a requirement of claims is disputed. janice mueller claims that an inoperable invention may fail to satisfy the enablement requirement under 35 u.s.c. Â§ 11
United_States_patent_law