What puzzles me is that most of the people in the pro-patent camp are usually fairly smart people. In my opinion there is a disconnect between the stated purpose of patents and observable reality. Surely smart people should at least feel uneasy about these disconnects?
As a means for sharing knowledge, patents are an obsolete mechanism. If you have ever worked for a large corporation you know that patents are treated like toxic waste. Not only will you be strongly disinclined to base important technologies on (someone else's) published patents, but even acknowledging their existence is often frowned upon. If you talk about, analyze or even just mention the existence of a patent that is somehow related to what your company does, chances are that you will get a telephone from the patent lawyers of your company instructing you that it is verboten to discuss patents in any medium that can later be subject to subpoena. Repeat offenses can lead to disciplinary action.
When was the last time you trawled through the patent databases in search of solutions for your technical or scientific problems? Well, most likely the answer is "I don't". You only ever check the patent databases when you need to figure out how much risk you are exposing yourself to. And even then, you don't talk about it because you don't want anyone to be able to prove that you willfully infringed on their patents if it should ever come to that.
Knowledge is shared in scientific journals, books and articles as well as less formal channels such as blogs, open source code and online discussion.
Patents do not represent repositories of usable knowledge -- they represent repositories of forbidden and dangerous knowledge.
Patents themselves do not protect your invention -- litigation protects inventions.
This means that unless you have substantial resources to fight costly and year long battles in court, and a large patent portfolio of other patents that can be leveraged against any threat, your patent is virtually worthless. This means that patents are mostly the domain of large companies or well-funded patent trolls. Which again means that patents do not benefit the independent individual innovator. Nor does it favor startups and other financially constrained entities. Patents protect incumbents. As a mechanism for rewarding independent innovation it does not work.
This largely invalidates the stated purpose of patents: to encourage sharing knowledge while providing a head start for innovators.
Recently I have read a lot about the pharmaceutical industry and its relationship to patents. Since I have never worked in these industries I can't really tell you how this affects practical engineering in these industries. I would expect that engineers are just as uneasy around patents as in the software industry. Perhaps even more so.
The numbers suggest that patents can possibly be blamed for the stagnation in development of new drugs to address health problems of the poor. The industry spends most of its budgets on marketing, lobbying and administration -- and what little is spent on actual R&D seems to focus on finding replacements for drugs that already have the desired efficacy. Curing the ailments of the poor, in particular those in jurisdictions where intellectual property rights are tricky, isn't good for shareholder value.
It would appear that the main purpose of pharmaceutical patents is to protect shareholder interests to the detriment of public health.
And we haven't even touched on the horrible mess that is patents as applied to agricultural intellectual property.
In all seriousness: I really doubt that preserving patents is in the public interest.