Sunday, October 4, 2009

Reality is When Nature Says No

Reality is when Nature says No--Philip K. Dick

Almost all of the Ten Commandments given to Moses on Mt Sinai are prohibitions--a big list of moral "thou shalt nots". Likewise in physics, some of our most precious intellectual possessions are also a list of material "thou shalt nots"--strict limits placed by Nature Herself on what can or cannot happen in the world. These negative commandments were not handed down in stone tablets but are based on the best knowledge that human have gained so far concerning the implacable and impersonal laws that seem to us to govern the entire Universe.

Situations where "Nature says No" are of great interest to scientists as they can motivate deep investigation into the details of how Nature enforces Her prohibitions as well as encouraging debunkers to attempt to find loopholes in Nature's prohibitions who in their failure might teach us even more about Nature's ingenuity in enforcing Her rules. Outlaw regions where these prohibitions are flaunted are places where a brand new physics is sure to emerge.

In casual review of the laws of physics I've isolated eight examples of "thou shalt nots" in the material world.

#1. No perpetual motion of the first kind. This law prohibits machines that produce more energy than they possess when they start.

#2. No perpetual motion of the second kind. This law prohibits machines that operate by extracting energy from random thermal motion.

#3. No faster-than-light motion and/or signaling: a prohibition discovered by Albert Einstein as a consequence of Special Relativity.

#4. No perfectly accurate joint measurement of complementary variables. Otherwise known as Heisenberg's Uncertainty Principle.

#5. No non-contextual reality can underlie the facts of quantum mechanics. Otherwise known as the Kochen-Specker Theorem.

#6. No local reality can underlie the facts of quantum mechanics. Otherwise known as Bell's Theorem.

#7. A single quantum cannot be cloned--a fundamental prohibition proved by Wooters & Zurek in 1982.

#8. A pair of quanta cannot be wed--a fundamental prohibition proved by Nick Herbert in 2008.

I welcome comments and nominations to this list. We need at least two more physics prohibitions to match or exceed the classic "thou shalt nots" handed down to Moses.

1 comment:

The 27th Comrade said...

#9 No system of physical inquiry, such as logic, can be both complete and consistent. (Proven by Kurt Gödel.)