Nearly anything can be patented. Machines, medicines, computer programs, articles made by machines, compositions, chemicals, biogenetic materials, and processes, can all be the subject matter for a United States patent. To get some handle on the contours of patentability, it is sometimes easier to think of the things that cannot be patented.
Laws of nature cannot be patented. Had Albert Einstein attempted to patent general relativity, his patent application would have been rejected by the Patent Office, at least in the United States. General relativity is a law of nature like entropy, sunshine, and the vagaries of weather. Materials for atomic weapons cannot be patented, presumably because the Patent Office is happy not to have the recipe for these materials available for public consumption. Articles contrary to the public good are not patentable. Since the buying and selling of human organs is illegal in all of the U.S., systems or methods that are dedicated to enabling the commercialization of human organ exchange would not be patentable.
Aside from these few categories, virtually anything that is new, useful, and nonobvious can be patented. To fully appreciate the bizarre range of inventions accepted by the Patent Office, visit the online patent database at www.uspto.gov.
One of my favorite intellectual curiosities is studying perpetual motion machines. Since a perpetual motion machine has never been built, it is not that difficult a subject to study. For some reason, though, the idea of building and patenting perpetual motion machines has been the Holy Grail to our world’s population of technical wackos – and there have been many. Although the exact definition of what constitutes a perpetual motion machine remains unsettled, at minimum it consists of a machine that, once set in motion, will continue in motion without ever stopping and without the influence of any further forces required to keep it going. An example would be a pendulum that, once started, never stops.
The obvious problem with perpetual motion machines is that in our earthly world, negative outside forces such as friction and gravity always work to retard and prevent true perpetual motion. More importantly from a patent definition standpoint, since a perpetual motion machine can never do work, otherwise the energy in the system would quickly be drained, can it really be called a machine? That is, do all machines, by definition, do some work? So even if a perpetual motion machine could be built, it might not even be patentable since it may not be truly useful, except perhaps as a novelty item.
In any event, if you do plan to file a patent application on a perpetual motion machine, be prepared to provide a working demonstration to the Patent Office – it is the only non-life sciences invention I am aware of that still requires the submission of a working model.