Should software patents have shorter life spans than other patents?

There are a lot of strong opinions with respect to software patents. Many people are highly critical of them because they feel that copyright alone is enough protection for software. The argument goes that copyright is a better fit than patent law.

For example, copyright is self-executing. That means that you get a copyright in your program as soon as you write it. In contrast, a patent is obtained only after filing and prosecuting - and in the process spending a lot of money on - a patent application.

Moreover, copyright is supposed to protect a specific expression - not broader ideas found in that expression. One major argument against software patents is, that in order to maintain the lightning pace of software innovation, developers must to be free to use general concepts pioneered by others so long as they don't copy the actual code.

It's basically a "square-peg-in-a-round-hole-type argument. That is, patents don't make sense for software because software is too different from the other things, like new chemicals and machines, that patents were originally designed to protect

Assuming there is a problem as some argue, maybe the solution is making patent law a better fit for software. One idea mentioned yesterday at the 23rd Annual Intellectual Property Law Conference of the American Bar Association was shortening the lifespan for software patents.

Currently, most patents last for twenty years from the date they were filed. At yesterday's conference, Judge Newman - who sits on the U.S. Court of Appeals for the Federal Circuit - commented that maybe a shorter lifespan of 5-6 years makes more sense for software patents.

That type of change would have to come from the legislature - not the court system. But Judge Newman's comment is still interesting. Given the short product life for software, does it make sense to shorten the patent life for software inventions?