I'd like to know how to define logical conditions to manipulate them. For example, say I have a list list of pairs of numbers, and I want to Select those which satisfy some condition
cond = #[[1]] > 0 &;
Then I just have to evaluate Select[list, cond]and it works. But if I have several conditions
cond1 = #[[1]] > 0 &;
cond2 = #[[2]] > 0 &;
then both Select[list, cond1 && cond2] and Select[list, cond1 || cond2] always give an empty list. How do I have to combine the conditions inside Select[ ] so that it understands the logical connection between them ( AND or OR)?