[ching_wow_ka]

That's right; we can't know for sure and I'm sure you'll get some backlash for this comment. As with everything though, we need a balance.

If we say that we can't know for sure and give up, then no advancements would ever be made in any field. On the other hand, we should recognize that science does not claim to provide us with certainty. Many of us speaking "objectively" with scientific "facts" often become emotional and arrogant when speaking to anyone who doesn't agree with our conclusions.