Correct, Eugenics is not a science, it is a social movement that was based on science, Darwinism to be exact. It attracted all number of scientists back in the day.
I think that most of the christians I know would not agree that they are good because god tells them to be. You seem to like putting words into the mouths of others.
The fact is that religion has been with us from the dawn of time. It is there because both religion and religious experience are a beneficial evolutionary adaptation. You would casually cast that off and claim that science can solve all our every day moral questions. Science has no process to address morality.
You may want to take a look at the Sam Harris video above, it answers a lot of your questions, and is only 20 odd minutes long. It talks about morality as the intended harm, or benefit, of conscious creatures (our utopia being the height of human happiness and well being, and the worst case scenario being the deepest misery and suffering. If something is moral it is done to bring us closer to the utopia, and if immoral, it is done to bring us closer to the latter). We can all agree that fresh food is better for humans than poison, knowledge over ignorance, etc.. Science can and does bring about the conditions to create technology to better human existence. Morality has evolved in humans to more efficiently pass on our genes (the only intrinsic purpose of life). We evolved in tribes of about 150 members, and each member had a strong likelihood of sharing genes with the other tribe members. So, risking one's life for another member made sense biologically, since you were likely protecting your own shared genes. As societies grew larger and more complex, the chances of sharing genes with a stranger is quite low, but we still have the remnants of our older tribe mentality. So, we often still see people risk there lives for, or at least go out of there way to help, others. Hence, we have altruism. If science has no place in handling moral issues, religion has much, much less...
If it did, perhaps we wouldn't have developed nuclear weapons. If science had some sort of internal moral compass or process why do we have these obvious failures of morality in experimenting on human beings.
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Science showed us how to develop the technology to harness nuclear power. It is up to human beings to develop the technology to better humanity (clean, efficient nuclear reactors), or to harm it (nuclear weapons). The technology the scientific method brings about is not a moral issue or the responsibility of science, that onus is on human beings. Most technology developed from the scientific method can be a double-edged sword. As far as the immoral experimenting, that is done by immoral people misusing science. Even when sacrificing the few to save the many, most agree that this immoral as most of us don't want to live in a society in which we could be sacrificed to others.
The idea that some guy up in the sky is watching you and doesn't want you to kill people is still far advanced over any reason science can give to not kill people.
I disagree. Cowering to a vengeful parental figure is not morality, and is a disgusting notion to a healthy adult human being. When my son does or doesn't do something for threat of being punished, that is simply self preservation and I am not impressed. When his actions are based on his inner sense of right and wrong regardless of the consequences to himself, he is being moral and I am proud.
.If anything, science suggests the planet is overpopulated and humans should be killed. Is that what we can expect from a culture who obtains it's morality from science?
Not at all. Using science and technology, people are finding ways to feed, clothe, shelter, and educate more people using less land, money and resources. Ultimately, science and humanity is the only hope any life has to continue, as we will have to eventually leave this solar system before our sun dies out or goes nova. Religion, the supernatural, aliens, dolphins, chimps or cows will be of no help. Go Science, Go!