There is no precise definition of the types of inventions which can be patented. Patents for inventions began with the Statute of Monopolies in England in the year 1624, with patents being allowed for “any manner of new manufactures”.
Since then the scope of the term “manner of manufacture” has evolved as courts have made decisions on a case-by-case basis.
In Australia, you can get a patent for an invention that belongs to a useful art, as distinct from a fine art, providing a material advantage which has value to the country in the field of economic endeavour. It is not possible to get a patent for an innovation which is purely aesthetic.
Other types of things which you can’t get a patent for include mere discoveries, mere ideas, mere schemes or plans, scientific theories, mathematical algorithms, and laws of nature. For example, if you discover a new type of rock you can’t get a patent for the rock but if you can think of a useful method of using the rock you can get a patent for that method.
Business methods and computer implemented methods can’t be patented if they just relate to intellectual information, but they can be patented if they produce some physical phenomenon or effect.
In Australia, you can get a patent for a method of treating humans, but you can’t get a patent for a biological process for creating a human. You can’t get a patent for a naturally occurring micro-organism, but you can get a patent for a newly created organism which has useful new properties.
The rules on patentable subject matter vary from country to country, particularly in the fields of biotechnology, methods of medical treatment, computer-implemented methods and business methods.