Atmospheric noise & fair coin flipping

[Tim May]

On Sunday, July 14, 2002, at 05:45  AM, gfgs pedo wrote:

> hi,
>
> Does a fair coin exist in real world?
>
> Like as according to Allan Turing-an event is defined
> by set of  certain parameters governing the event at
> that instant.
>
> by redoing the same experiment-do we always have the
> same set of parameters that previously defined the
> coin.

No, certainly not. We have limited measurement precision, currently 
something like 12 decimal places for most mass/gravity/thing parameters. 
Even our theory of QED is "only" good to about 23 decimal places, less 
in any real world laboratory. The result? The errors will come "marching 
in" from beyond, resulting in variations in coin tosses, billiard table 
evolutions, etc. Cf. a large body of (mostly old) stuff on this. Google 
is your friend.

>
> it is said that atmospheric noise is random but how
> can we say for sure.

No, no sequence (of bits, symbols, pressures, etc.)  can ever be 
"proved" to be "random." Cf. Chaitin, Kolmogorov, or more popular 
accounts in, say, Rucker's "Mind Tools." Also covered in archives of 
this list.


You ask a lot of questions. I encourage you to find some of the basic 
books, use Google, and to think deeply about questions before phrasing 
them here.


--Tim May