*This month’s post may make a valid point. Or it may not. Or it may be impossible to tell, the concept of which itself may or may not make sense by the end of the piece!*

How do we handle things we *don’t know*? More precisely, how do we cope with things we *know* *we don’t know*? All right then: how do we handle things we *know we can’t know*?

As is the nature of this blog, the examples we’re going to discuss are (at first, at least) taken from the fields of computer science and mathematics; but there are plenty of analogies in the other sciences. This certainly isn’t a purely theoretical discussion.

On the whole, we like things (*statements* or *propositions*) in mathematics (say) to be right or wrong: *true* or *false*. Some simple examples are:

- The statement “
*2 > 3*” is*false* - The statement “There is a value of
*x*such that*x < 4*” is*true* - The proposition “There are integer values of
*x*,*y*and*z*satisfying the equation*x*” is^{3}+ y^{3}= z^{3}*false*

OK, that’s pretty straightforward but how about this one?

- “Every even number (greater than 2) is the sum of two prime numbers”