Paul Graham recently published an article entitled What You Can't Say that urges us to challenge our ideas of what is acceptable socially and morally. Here are some excerpts, but I encourage you to read the whole thing - it's a great social investigation.
In reference to terms like "heretic", "blasphemer", and more recent incarnations like "hate-speech" :
Labels like that are probably the biggest external clue. If a statement is false, that's the worst thing you can say about it. You don't need to say that it's heretical. And if it isn't false, it shouldn't be suppressed.
On why scientists tend to realize and accept socially "unacceptable" ideas more easily_
"A good scientist, in other words, does not merely ignore conventional wisdom, but makes a special effort to break it. Scientists go looking for trouble. This should be the m.o. of any scholar, but scientists seem much more willing to look under rocks.Great thinkers don't dress fashionably because they've transcended the level of caring about petty things like fashion.
Why? It could be that the scientists are simply smarter; most physicists could, if necessary, make it through a PhD program in French literature, but few professors of French literature could make it through a PhD program in physics. Or it could be because it's clearer in the sciences whether theories are true or false, and this makes scientists bolder. (Or it could be that, because it's clearer in the sciences whether theories are true or false, you have to be smart to get jobs as a scientist, rather than just a good politician.)
Whatever the reason, there seems a clear correlation between intelligence and willingness to consider shocking ideas. This isn't just because smart people actively work to find holes in conventional thinking. I think conventions also have less hold over them to start with. You can see that in the way they dress."
The whole article reminded me of a point frequently addressed by Bill Bryson in his book A Short History of Nearly Everything (and reinforced by every good science course that I've ever had). The biggest scientific discoveries always express ideas that go against the status quo. As a result, people often discount the ideas, and mock or shun the scientist responsible. All too frequently, the discoverer is only vindicated posthumously, at which point he gets several science buildings or a grant named after him. What a consolation prize...