You are hanging on a cliff holding on to a stone, firstly probably you will shout for help hoping for someone to be there. Desperately praying for someone to hear your voice and come there to help. I agree thats just natural human instinct. But what if there is no one, no one to hear your voice or to help you out. So what now.... There is a very simple choice you have. You can continue shouting until your body finally give up and you probably die. But there is another thing you can do, you gather all the strength you have got and carefully try climbing up yourself. I know its gonna be tough and I don't deny you may fail and that does mean you might die. But I still think its atleast worth trying. I didn't really imagined it just a small metaphor.