why declare boolean value before functions didnt work?

Hi Guys, The clockIsPaused (boolean type) only returns true if I declare it in the function. But why at the top or before the function, it didn't work? I thought we can input all the values when we declare the var which type and before all function start?
(I know it's sounds silly,that function is where all the process of code start) I'm just curious. #pragma strict var clockIsPaused : boolean = true; function Start () { //clockIsPaused = true;// even if I put the boo lean in the declare top it, //it is still as false, why? } function Update () { Debug.Log(clockIsPaused); }