To a great extent, it is our human conscience that defines who we are. Morals and moral codes are not enough to keep humans on the right path. Not even the law can do that all the time.
Only conscience stops a man from stealing something in the dark when no one else is looking.
Without human conscience, many researchers into the field argue that the behaviours of human beings would become practically unpredictable.
The boundaries between actions that are rational and those that are not would become blurred and there would be nothing to hold us back from whatever action we contemplate, be it right or wrong.