I was just wondering they say that science are perfect. How come that they cant give a pure answers to some issues to like why do people dream? They say that it is on the psychological effect but it is not certain
Why is that there are left handed persons? Any thoughts about this?
Because science is not perfect, at least not at the moment. Real perfect science is like true communism, it will probably never happen. Humanity will always uncover new truths about the world we live in and science will change accordingly. The questions you raise are simply beyond the current capabilities of science but one day they'll be answered, just like hundreds of years ago nobody knew what's the reason behind the day and night cycles but then science evolved and we learned about the planet's rotation.