Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Path: utzoo!mnetor!seismo!columbia!heathcliff.columbia.edu!zdenek From: zdenek@heathcliff.columbia.edu (Zdenek Radouch) Newsgroups: sci.physics Subject: Re: Minor nit on psi experiment Message-ID: <3782@columbia.UUCP> Date: Wed, 5-Nov-86 19:29:17 EST Article-I.D.: columbia.3782 Posted: Wed Nov 5 19:29:17 1986 Date-Received: Wed, 5-Nov-86 23:01:17 EST References: <236@sri-arpa.ARPA> Sender: nobody@columbia.UUCP Reply-To: zdenek@heathcliff.columbia.edu.UUCP (Zdenek Radouch) Followup-To: net.physics Distribution: net Organization: Columbia University CS Department Lines: 40 In article <236@sri-arpa.ARPA> KFL%MX.LCS.MIT.EDU@MC.LCS.MIT.EDU writes: >From: "Keith F. Lynch" > > A true random number generator might be a speck of radium with a >Geiger counter next to it. A silicon device, i.e. computer, can only >be a ~rpseudo-random number generator. The numbers that are produced by >it may be well distributed, but they only APPEAR random - because of >our lack of knowledge of the algorithm.... Sorry, the life isn't that simple. Let's not argue about true or pseudo random numbers, philosophers will do it for us. We use computers because it's easy to get any distribution we want and the process is controlled. If you don't understand the mechanism of generating the numbers you just get some numbers and you have to analyse them. As a result you could say they have such and such distribution, but that doesn't imply that the numbers to be generated next will have the same property. As far as the examples you used, a Geiger counter counts 0,1,2,3,4,5,6.... That sequence can hardly be considered to be random. The only way to make it what you call "true random number generator" would be to build some fairly sophisticated hardware around it. Even then it wouldn't generate the numbers with required distribution; it's simply too complicated. It would be much simpler to use an analog silicon device in a mode where "you lack the knowledge...", but this method (it is actually used) is also hard to control. A mathematical model is just the easiest and most reliable approach. zdenek ------------------------------------------------------------------------- Men are four: He who knows and knows that he knows, he is wise - follow him; He who knows and knows not that he knows, he is asleep - wake him; He who knows not and knows that he knows not, he is simple - teach him; He who knows not and knows not that he knows not, he is a fool - shun him! zdenek@CS.COLUMBIA.EDU or ...!seismo!columbia!cs!zdenek Zdenek Radouch, 457 Computer Science, Columbia University, 500 West 120th St., New York, NY 10027