Patent Basics: Utility
Patent law is designed to promote innovation in “science and useful arts.” It’s right there in the first Article of the Constitution: in order to be patentable, an invention needs to be useful in some way.
In general, there’s relatively little hullabaloo over the utility requirement; it’s usually kind of self-evident whether an invention is useful or not, unlike novelty or nonobviousness, which are a bit more difficult to prove or disprove. However, there has been a good deal of controversy recently in the burgeoning realm of genome patents, where some companies have been accused of patenting genes before their function is fully understood.