PHeMoX,
"All I'm asking here is 'why' do you think so." Divine Revelation- the bible. The same revelation that gives us understanding of how logic and science are possible.
"I personally believe death is the only real penalty we can get" You cannot know this or anything about the afterlife and judgment without revelation. But if you reject the bible about these things you will also reject the justification for logic and science and morality.
"What exactly do you mean here?" I mean that your worldview cannot account for logic and science etc. You can score a 100% on a math test but in your philosophy this is not possible- therefore your philosophy is wrong and should be scrapped. The Christian can explain how a finite, particular, changing person can use the universal, infinite, invarient laws of logic accurately. In your worldview this is an impossibility, it doesn't make sense, and this is why your worldview should be obviously in error to you.