There are two broad categories of Constitutionally protected creations, those that are of artistic value and those of utility.
In the area of artistic creations, the greatest portion of the invention is in the expression. For example, the effort to produce a superbly written, though not well thought out, blog posting is almost all in the expression of the idea. The effort, and thus the protection, is centered around the effort it took to create the specific embodiment, and a copyright is in order.
Ideas that are inherently useful are protected by patent, and to a much lesser extent by copyright. Because the usefulness of the idea can have great commercial value, the protection of the idea is much more limited than copyright in terms of length, and much more difficult to enforce.
Looking at software, there are some who believe that copyright affords the best protection. But where does software fit in the spectrum?
Software looks like written text. It is a compilation of characters that expresses an idea on some level. In fact, it is a very particular and exacting way to express an idea. So much so that by changing one of a million characters in a software program may cause it to completely malfunction.
Software is “written” and can be easily “copied.” In many aspects, software looks and acts like this posting: an artistic expression of some idea.
However, when you look at it a little deeper, software does not behave like the text of a book, but more like the elements of a machine.
The software is what makes a computer perform its functions, and to a very great extent, makes many different devices operate the way they do, from toasters to airplanes.
Software is useful in many different forms. A software program that operates on a robot may enable the robot to pick and place certain objects, but a “virtualized” version of the same software may simulate the operations of the device, which may help an engineer design a fixture or perform operational analyses. Both implementations use the same software, and both have utility. Both should be protectable by patent.