Neil Barrett

York

Writer

Re: 'Hey, gizza job'

Thanks for the comment; people taking issue are always welcomed!

You're right, of course, that "this statement is true" is paradoxical rather than undecidable. To be (pedantically!) correct, I should have said that we have two sets: the set of all true statements and the set of all false statements. Assigning "this statement is true" to one or other set is then undecidable. But with only 1,000 words to play with, I simplified it!

You're also right that we have two ways of determining whether a biological virus is harmful. Our immune system can 'recognise' it as an example of a harmful thing previously encountered and then kill it; or we can allow it to live and see whether it does anything harmful. The problem, of course, is that the harmful activity might be permanently damaging to the host body.

The analogy holds for computation. We can scan the code looking for previously identified sequences of known harmful instructions; or we can execute it and see what it does. Of course, the 'what it does' might then again be permanently damaging, this time to our data set.

Neil