the thing is to let the kids think for themself
IMHO that's initially not possible.
Parents provide a worldview for their children, which later gets challenged by interaction at school and in general life.
I would suggest that to think that a young child is genuinely going to be able to think for itself in an adult manner is a misnomer. Otherwise, why is it that children are not held accountable for certain crimes, etc.?
Edited to add:Further, I would contend that to leave a child without some kind of framework to work from would be remiss.
Alternatively, why do you think it is that children go through the "why?" stage?