Thursday, May 27, 2010

schroeding & turing

Schroeding's Cat is the typical name for a thought experiment about the oddness of the Quantum model of the Universe. It is an artificially constructed scenario where the normally microscopic quantum level effect selects a macroscopic change in the state of the Universe - i.e. the decay of 1 single atom triggers the life or death of a large creature (a cat is presumably on the order of 10^24 molecules) - Life or Death states of the cat are
quite visibly distinguishable to a human observer. Of course a simpler trick would be to have a critical mass of fissile material, less 1 atom, and then just add that 1 atom and then see if it decays or not and does so triggering the chain reaction or not....that would also be quite visible and not very distorted by emotive weird observable things (when is the cat dead? what is life? :-)

Turing's test of intelligence decides the matter based on a human observer's ability to distinguish the responses of a black box to a set of questions (sent over some teletype line to avoid any complex non verbal comms). It can be generalized.

Some confusion arises when thinking about Schroedinger's Cat ("paradox") and observers.
Note that the state of the cat is actually created by an observer (the geiger counter described in the wiki article above is the thing that detects the decaying atom, and triggers the hammer to break the flask of cyanide that kils the cat (probably). The uncertainty is purely about when the decay happens. An observer of the dead cat is a secondary thing - we can assume fairly certainly the cyanide kills the cat (all nine lives) so in fact all we need is a red light on the box that says the geiger counter detected the atom decaying. The confusion arises because two words are misused from natural language:

  • observer
  • description

    The observer does not have to be intelligent.
    The description is not obvservable.

    Hence we can't use this to talk about consciousness, and there is no paradox (descriptions of intermediate unobservable states are figments of maths - only if actually observable are they interesting (e.g. remote entaglement).

    The point of mentioning the turing test is that Schroedinger also conflates two things:
  • simple observation (detect decay from emitted particle
  • complex observation (is the cat alive).

    Is detecting life, perhaps a nice turing test?

  • Sunday, May 23, 2010

    remarkable engineers

    this is a fun read if you like these sort of mini-bio things :-
    Remarkable Engineers follows similar excellent books on maths&science. But it is an interesting book for its lack of people that I would regard as engineers from Ancient Greece, Arabia, and China - however, within its well-defined model of what an engineer is, it is interesting (seems like you not only have to build something, you have to patent and sell it, and preferably be Scottish:)

    Thursday, May 20, 2010

    1 mole of stars. Avagadro, state and human perception of scale

    so reading
    The Eerie Silence by Paul Davies,
    he points out that there are estimated to be around 10^23 starts in the universe around now....this is an interesting number (like all numbers) which is around Avagadro's number which is the number of atoms in 12 grams of carbon 12
    or roughly 24 liters of air at STP.

    one amusing number to play with is the number of molecules in a glass of water, which is MUCH more than the number of glasses of water in all the oceans of the Earth.

    So the number of stars is in between.

    maybe, they are the same thing.