> It's quite easy to show the ill effects thereof.

I haven't found a study that does so convincingly.

> It's harder to evaluate the beneficial effects...

Agreed, but studies have attempted to do so. For instance, the Moser paper clearly shows greater diversity in innovative activity as people started tinkering in fields that had no protection, and hence little incentive to innovate, before patents were introduced.

> My argument is that those benefits no longer outweigh the costs.

And my argument is, with all the studies out there, it is impossible to compare the benefits and the costs as they are largely orthogonal.

> I read the meta-study you linked to, and found it quite unmoving.

Yes, that's why I pointed to the meta-study. I find it fairly balanced on the whole, identifying benefits as well as costs. The point was not to convince you either way, just to highlight that the situation is pretty nuanced. For instance, while classical assumptions (like disclosure) may not hold, there are a number of alternative ways patents encourage innovation (e.g incentivizing R&D investment, signalling, facilitating VC funding and entry, etc.)

> Their discussions and linked studies of efficacy at promoting invention itself seem far too focused on direct economic value as a measure of invention value, and the remainder of their study focuses almost exclusively on economic value.

That is how most of this literature goes, unfortunately, because invention value is impossible to measure at scale. Some metrics have been devised (e.g. number of citations, etc.) but those have also been found lacking. And so the best they can do is find proxies in economic indicators.

> Both, and other cases as well...

Can you point to some examples of a novel technology that would have been available in the market if not for patents? Note that from-scratch re-implementations are just "new", not "novel".

> In the other case, someone else builds a better product and puts the first out of business, ...

Doesn't have to be a better product. It just has to be cheaper because the second company did not incur the costs and risks of inventing a new product line. I've heard "Copycats" by Oded Shenkar is good book about this phenomenon.

> That's leaving aside the very likely scenario that a patent intended for such a purpose cannot be used "successfully" against a bigger company... However, I can readily bring to mind numerous instances of patents used to threaten new entrants to a market, or used for trolling by companies providing negative value.

Again anecdotally these scenarios may seem common, but a limited empirical study suggest they (e.g. predation profile) is uncommon: http://papers.ssrn.com/sol3/papers.cfm?abstract_id=1396319

> By contrast, not a single case comes to mind of a patent used as you've described, to "defend" a product by the inventor's company against a larger company.

Since this is a Microsoft thread, appropriate examples would be Stax electronics and i4i. See also the Chien paper above which may have more numbers.

> I don't believe technological progress will grind to a halt, or even slow down, with patents (or even just software patents) abolished. I won't necessarily argue with as much confidence that it will massively accelerate, either, though it certainly will in areas I care about.

Depends on what you count as "technological progress". I don't necessarily count re-implementations of existing technologies as progress.

> But I can honestly say that I've never once seen a patent lawsuit in which I could muster the slightest sympathy for the plaintiff or the slightest belief that they deserve anything. And I've read a substantial number of patent lawsuits, both contemporary and historical.

I guess if you think, say, the Wright brothers didn't really make modern flight possible or that Apple didn't really revolutionize the smartphone industry, not much I can say.