In order for an invention to receive the benefit of a patent, there are certain requirements the invention must meet. For example, the invention must be made by man – that it, things which occur in nature are not patentable. So, if you discover a remarkable new fish – one which nobody has ever seen before – that fish having occurred naturally could not be the subject of a patent. Strangely, if you genetically alter a fish to produce new traits that do not occur in nature, you could be entitled a patent on that fish!
There are five critial requirements that must be satisfied. These requirements are sometimes called 'patentability requirements'. Each of these patentability requirements are presented in the discussion which follows here designed to introduce these concepts rather than to provide detail treatise thereon.
As you contemplate these patentability requirements, it is important to remember that the first four of these requirements are either 'Yes' or 'No' answers. Certainly a creative patent practitioner can offer evidence and arguments that can help save the day, but these requirements are either satisfied or they are not. The last requirement — the adequate description requirement — is one that is completely within the purview of the one who is writing the patent application. In other words, if you have an invention that satisfies the first four requirements you can still find yourself not entitled to a patent because you have not described the invention as the law requires. For this reason many inventors and virtually all companies hire a patent attorney or patent agent to assist them in preparation of a patent application.
As mentioned above, a naturally occurring fish is not patentable subject matter. Algorithms are also not patentable. Items which can only be used to cause harm or are strictly illegal – are not patentable subject matter. A patent for a tabacco which caused one to believe it was another more expensive species was rejected as not patentable. There are many others.
An invention must be 'Useful'. Things which are useless are somehow not deserving of a patent I suppose – however I would argue I have seen many granted patent for things I considered useless. This is the easiest requirement and any argument towards usefulness tends to convince the patent office. Nice guys that they are!
An invention must be 'New'. That is, If something identical already exists before you invented it, then it is not patentable because it is not new.
An invention must not be obvious. This is a tough one. We (patent practitioners) spent 90% of the time trying to build legal arguments why things are not obvious. From 1966 until 2008, this wasn't really so bad as the rules for obviousness were long tried and tested. It was pretty easy to argue a case in favor of non-obvious. Then, the Supreme Court came along and tossed in KSR-Teleflex. Ooops. That changes most everything. New rules and new arguments. We'll need about 5 to 10 years of good case law before we know where we really stand on this one. Fun and Joy! I hope your case does not become one which ends up setting a new standard! …at the same time, I am happy to take it if it is.
An invention must be adequately described in a patent application. If you are going to get a monopoly, then it is essential you set down precisely what it is you have invented. Seems fair to me.
If you really love reading, you'll find all you ever wanted to know about patentability right here: Patentability - MPEP. I must warn you, this could put you to sleep so please don't operate heavy machinery while reading this.