I state the following knowing full well that the US Patent Office is often frowned upon by Randi and many others here. I am fully prepared to take the brunt of jokes at my expense.
I am a relatively new employee of the USPTO, currently training to be a patent examiner. There's a ton of information to be learned, but among it is this little tidbit: the patent office does its very best not to grant patent to ideas that break the laws of nature. There's a term for it, "judicial exception". The term refers to the fact that originally, the courts deemed as patentable "everything under the sun". Then they thought about it, said "oops", and created judicial exceptions. Judicial exceptions include:
-laws of nature (you can't patent gravity)
-abstract ideas (you can't patent the color blue)
-mathematical constructs (you can't patent pi)
-things that break the laws of nature (you can't patent PPMs)
When we see one of these, they come under 35 U.S.C. 101. They are unpatentable.
(By the way, Randi was incorrect. It is true that the one and only invention the USPTO requires a working model of before it grants a patent is a PPM. I could quote you chapter and verse, if anyone wants it.)
Mind you, sometimes it's difficult to tell. The patent attorneys that the applicants hire couch the invention in so much language that it's often tough to figure out just what they are claiming to have invented.
I think one of the reasons the USPTO comes under fire so much is that it grants patents for seemingly stupid stuff. The thing is, the PTO isn't charged with making sure that an invention works, or is marketable, or is a good idea. We're only charged with making sure it hasn't been done before (basically. That's actually a very simplified way of putting it.)
This is why you get patents for stuff like "nose bleed detectors" or whatever. It's not our job to make sure the invention isn't stupid, just that the application is proper.
My 2 cents. I now open my arms and embrace the flames.