Monday, May 2, 2011

Patent reduction redux

In my last post I presented a translation of a patent into Haskell. This post went up on Hacker News and Slashdot, and I got over 25,000 page views plus a lot of comments. There are too many comments to respond to individually, and many of them cover similar ground. So here is a more general response to the main issues raised.

Its trivial

Well, yes, in the computer science sense it is. We all know that any algorithm can be written in any turing-complete language, and the Lambda Calculus is turing-complete. QED.

However when I read court judgements related to patentability this never gets mentioned, not because judges are too stupid to understand the point, but because as far as I can tell no lawyer has ever tried to put it in front of a judge. I'm not sure exactly why this is, but I suspect that it is a combination of the general squishiness of the law (see below) and the fact that you want to base your case on a tried-and-tested legal theory rather than building something completely new. From a lawyer's point of view an obscure mathematical theorem (most lawyers have never heard of Turing) looks like a very shaky foundation for a legal argument.

So it seemed to me that if I could convert this abstract theoretical point about turing-complete languages into a practical demonstration that directly addressed a key point of law then it might make a big difference. Sure its a small step for computer science, but it could be a giant leap for legal thinking.

The law is squishier than that

Eben Moglen has said
... the hacker belief that laws are form of code [creates] a particular frame of analysis for legal questions. [...] one thing which lawyers around the world all share is an awareness of the squishiness of law, it is by no means the hard arthropod carapace for internal soft organs that non-lawyers have a tendency to assume it is
Moglen is undoubtedly correct, and when I look at legal judgements I often seem to discern a judge trying to construe the facts and law in a way that will deliver what s/he believes to be justice in the wider human sense as well as in the strict legal sense.

But judges are still constrained by the law; however much they might want to, they cannot look at evidence conclusively showing fact X plus a law saying "if X then Y", and then deliver a judgement of "not Y". The trick is to provide incontrovertible evidence for X. To extend Moglen's metaphor, the law may not have an arthropod carapace, but inside the squishy flesh it still has a rigid skeleton of of laws that judges cannot bend at will.

The law / lawmakers are too corrupt; they'll just legislate around this.

I don't believe the application of the law in the US is anything like corrupt enough for this to be an issue. The worst one can say about the application of American law is that effective legal representation can be bankruptingly expensive for the little guy. But that's not a problem here.

Lawmakers are an issue; the leadership of America is routinely for sale to any sufficiently large campaign contribution. But the limits on patentability are long-standing and fundamental, and until the State Street decision in 1998 it was generally understood that computer software and other information-processing algorithms were not patentable. For the US legislature to change this basic principle of patent law seems unlikely.

Everything in the patent is prior art anyway.

Prior art is one of the most misunderstood things in patent law. Each claim in a patent is an entire invention; there may well be things in the invention that are prior art, but unless you can show that everything in the whole claim existed in a single entity previous to the patent priority date then you don't have prior art.

So the fact that hash tables and linked lists were well known before this patent is irrelevant. Of course if anyone can show actual prior art that includes everything in one of the claims then I imagine that the Red Hat lawyers would like to hear of it.

But all patents can be reduced to a formula / number, so this argument would abolish all patents.

This misunderstands patent law.

USC 35 II 10 defines a patentable invention as
... any new and useful process, machine, manufacture, or composition of matter, or any new and useful improvement thereof ...
This definition excludes mathematical formulae and physical facts from patentability. Leaving aside the fact that it is also well known, the quadratic formula is not patentable because it is not a useful process, machine etc.

The patent covers the physical realisation of the idea, not the idea itself. So publication of the patented material in any form is fine in theory; that is the whole point of the patent system. What you can't do is make and sell the patented invention. (An exception has been carved out here for ready-to-run implementations of software patents on the grounds that they contribute to infringement by the users, which is bad law but not part of this argument).

The 120 patent recites a computer running the algorithms to create a useful improvement in performance, so that makes it patentable.

In the State Street case the Court decided that a mathematical formula could form part of an invention, as long as the whole thing was a new and useful process, machine etc. This was a radical departure from previous US decisions, but it matches current European law (I don't know which came first) where mathematical formulae and computer programs cannot be patented "as such", but can be patented as part of an invention that achieves a "technical effect" (which seems to mean the same as "new and useful improvement" in the US).

However Bilski has now blown all that out of the water. The Court in Bilski specifically declined to endorse anything in State Street, and instead decided that patentability should be decided in line with three other cases. For more details see my post on this, but in essence it means that while a mathematical formula or algorithm can form part of a patented invention, it doesn't contribute anything to the novelty of that invention. Even if the formula or algorithm is completely new, for the purposes of the patent it is treated as "well known". Hence in the Diehr case (the rubber curing method) the invention was the use of a calculation to tell the mould when to open rather than a predetermined time interval. The formula to do this was part of the patent, but the invention was its use in a new kind of machine; one that opened based on temperature readings rather than a timer. On the other hand in the Flook and Benson cases the only novelty was in the formula; everything else was held to be already known, so the patents were disallowed.

In Bilski the central component of the invention was a formula for hedging bets in energy markets. All else was well known, so the patent was disallowed. The Supreme Court said:
Claims 1 and 4 explain the basic concept of hedging and reduce that concept to a mathematical formula. This is an unpatentable abstract idea, just like the algorithms at issue in Benson and Flook.
In this case the patent application itself contained the reduction of the concept to a mathematical formula. But clearly if the claims had left the formula unstated and merely listed an equivalent series of steps or assemblage of "means" (e.g. "a multiplication means connected to an addition means") then this would have merely been a change in the drafting, and it is well established that you can't make something patentable just by changing the words in the claims. So this leads to the following conclusion: any element of a patent claim that can be reduced to a mathematical formula is not patentable material, and the subsequent Section 102 analysis (to determine if the invention is new and non-obvious) must ignore it.

So in the case of the 120 Patent, all the claims come down to "a general purpose digital computer running software that implements a bunch of mathematical formulae". Running software on a computer is prior art, so there is no new invention here.


Jesse Pollard said...

I'll repeat here -
Would you permit your post "Patent 5,893,120 reduced to mathematical formulae" to be republished on Groklaw?

Paul Johnson said...

Yes, that would be fine. Sorry I didn't answer the first time, but I've been a bit busy.

Jesse Pollard said...


I'll find out what followup is needed - they may need some contact info and some copyright notification (groklaw uses Creative Commons for most things), and there may be some direct contact needed (verifying content by you).

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