Eh? Who mentioned souls?
You, typically, missed the point entirely. You aren't reading what we are saying, prefering instead to supply our end of the conversation from inside your own head, based upon the (completely wrong) assumption that I believe in God.
Let's say there is a drug that could make all human beings docile. Make them willing to work constantly for nothing more than food. Remove from them all emotional needs and desires. Effectively turn them into chemical machines. No pain comes from it, in fact it removes all pain, emotional and physical. It completely obliterates the individuality of all who ingest it.
Scientifically prove to me that it is wrong to use this drug on the entire population. That means, prove it. Not "show us there are chemicals in your brain", if you decide not to do it because of those chemicals that isn't logical. Logic is what takes place in the world, not in the mind. I want a logical reason, which can be verified using the scientific method, why it would be wrong to put this drug into the water supply.