Welcome to Saved by Science, a program devoted to the Humanist principles of fashioning a better world through the application of critical thinking, the scientific method, and our shared values as social primates.
What is Humanism? You can find a full description here, but in simple terms, Humanism is a life philosophy that embraces reality and encourages compassion - and who could possibly be against that? Who would adopt cruelty over kindness and irrationality over clear, crisp thinking?
With regard to the former, I suspect the large majority of people genuinely believe they're acting with kindness, even if their behavior would suggest otherwise to an objective, third party. As for clear, crisp thinking - that, unfortunately, is not one of our strong suits, because our brains didn't evolve in order to generate truth. Rather, brains which led to more progeny tended to be selected for, and that means we have all sorts of fascinating cognitive biases, mental heuristics, and exploitable susceptibilities built into the three pounds of wrinkly neural matter jiggling about in our skulls.
Now that science is getting a better feel for how the brain works, however, and how religion and other rigid ideologies can exploit its frailties, we can employ critical thinking to make wiser decisions about everything, from how set our policies to how we conduct our lives. Indeed, not only can we change how we think, but now that we've become a global civilization with the capacity to ravage every ecosystem on the planet, we need to change, and quickly, otherwise we'll be damning future generations to a needlessly hostile environment. Thinking critically isn't an esoteric nicety to be practiced by students of philosophy; it's an ethical responsibility that should be embraced by us all.