Here's a concrete flaw. The inventor must disclose the method. If you read the patent, and infringe, you're subject to triple damages. So there's a strong incentive to not read about how other people solve problems. Which pretty much defeats the purpose of promoting useful arts.
Furthermore, non-patent readers wind up infringing anyway. I would argue that someone completely unaware of the patent, coming up with the exact same system means that it is in fact obvious, and not really novel.
Although I disagree with most software patents, I don't think you're last assertion is correct. There is some hindsight bias going on here. What is obvious in 2031 may not be obvious in 2016. Just think how much the technology landscape has changed in the last 15 years.
The intent maybe so, but the practice is exactly opposite. Not only patents are being used to effectively block progress in certain areas for years (because many researchers can't or won't pay license costs and us such unable to incrementally build on existing knowledge), but reading a patent if you work in similar area is the worst thing you can do - after you red it, all you work will be contaminated by suspicion that you have used patented IP without licensing. So if you suspect there's a patent in some area you work in, the best thing to either pay somebody to search for patents but never read them by yourself, or to ignore the patents and assume the risk. Otherwise you are exposing yourself to claims even if your work is 100% original - you'd have to prove it's original and familiarity with the patent would work against you. So it gives huge incentive to impede flow of information.
Additionally, if you read any of the software patents, they are written in intentionally obscure, outrageously dense and purposely obfuscated language, as to sound more generic and vague and capture more "space". They have tons of claims which repeat the same thing with tiny variations, they describe most mundane things as if it were huge novelty, and they are made as hard to read to a common person as possible without switching to Sanskrit. They never increase sharing of any information and never are written with this goal in mind.
"[P]atents are being used to effectively block progress in certain areas for years (because many researchers can't or won't pay license costs." This is mitigated to some extent by the research exception: https://en.wikipedia.org/wiki/Research_exemption.
> Without patents, there are no incentives for publicly stating your methodology.
That can't be true. There are about 50,000 new phds a year, all of their dissertations are public. Those are all required to be novel, right? so clearly, it's not the only incentive. There are many incentives, recognition, fame, and funding to name a few.
> Patents increase the sharing of information, they do not reduce it.
Ok, sure, but reading the patent creates a minefield for any future work. Was it your idea or did you read it in a book? Some people can answer this question remarkably well, remembering the source for every concept they employ. If on the other hand, you're not good at this, reading patents is very dangerous. Triple damages encourages not reading patents.
> The second point is covered by prior art.
No, an infringing idea after publication of a patent is by definition not prior art. It can be a completely independent discovery, but it's still infringing. Again, independent discovery seems to indicate, to me anyway, it's obvious.
Do you know of anyone who has had a software development problem, searched a patent database, found a solution in the database, then implemented that solution? I know that I never have, if people actually do that I'd be interested to know what sort of problems they are working on.
Without patents, there are no incentives for publicly stating your methodology.
Not true at all. Huge amounts of mathematical research, scientific research, fashion design, and culinary innovation are shared with the public every day without absolutely no patent protection. When was the last time you read a story in a newspaper about a patent filing? How useful was the information in that patent to anybody?
From what I see that happens with patents in practice and from economics papers that try to model how patents affect the society the patents in general brings only harm.
It does not imply that narrow niches where patents can work do not exists, but it requires that any statement about benefits of patents must be backed up with credible data. And so far I am not aware of those.
The copyright is protected by the fact of publication.
Consider your code a piece of poetry and sleep well.
If someone else recites it, the world becomes better if the piece is good.
Patents are from industrial era of greed.
Furthermore, non-patent readers wind up infringing anyway. I would argue that someone completely unaware of the patent, coming up with the exact same system means that it is in fact obvious, and not really novel.