C & C

you fell sick.

the doc prescribed you two kinds of pills.

one is red, the other blue.

you took both of them.

couple of days later, you were all well again.

so is the red pill working or the blue pill working or both of them, you wonder?

the next time, you fell sick again, he gave you the same prescription.

you wanted to know whether it's the red or the blue pill that's working, so you took them separately.

red pills only, nothing happened.

blue pills only, nothing either.

both, all well again.

conclusion:

we can't tell whether it's the red or the blue pill that's working to cure the illness.

what we know is that, if we take both of them, it works magic (okay, maybe not so magical)!

hence, there's only correlations between the red or blue pills and its effectiveness but no absolute causalities of either kind.

yeah, C & C!

so next time when you want to say "it is because of A, B...", think again, before you speak.