Random number

Question

This sentence is given in the following website.

http://www.dotnetperls.com/random

"Random number generators cannot return truly random numbers. They return instead sufficiently random numbers".

What does "cannot return truly random numbers" means.

Vulpes · Answer

The random number generators typically used by computers are what's called 'pseudo-random'. This means that they are based on a complex mathematical algorithm which produces a long sequence of apparently random numbers which will in fact eventually repeat. Nevertheless the numbers generated do appear random and as the sequence can be 'seeded' (i.e. you can start at an arbitrary point within it) they are considered sufficiently random for most practical purposes. However the DNP article makes the mistake of thinking that since computers are deterministic they are limited to producing pseudo random numbers. In fact if one can use the computer to measure some natural phenomenon such as atmospheric noise they can produce 'truly random' numbers as well and there are services on the internet (such as random.org) which can produce such numbers. You may find this article illuminating: http://www.random.org/randomness/

Maha · Answer

Thank you for your explanation.