Freethinker. One who has rejected authority and dogma, especially in his religious thinking, in favor of rational inquiry and speculation.  American Heritage Dictionary  

Individual whose opinions are formed on the basis of an understanding and rejection of tradition, authority or established belief.  Wikipedia

Many people see themselves as "free thinkers," with minds open to new ideas and perspectives.  They describe themselves positively as favoring rationality, but in practice their negative self-definition seems to have more force.  Even when they turn out to have been wrong, freethinkers are proud of having resisted social pressure toward conventional wisdom. 

Freethinkers see the deck stacked against new or contrary ideas, and see their own brave contrarian stance as a needed antidote to unreasonable conformity pressures.  On net, however, freethinkers deserve much of the blame for resistance to new ideas.  Bryan Caplan explains:

Suppose you’re interviewing a smart guy [for a job], without a college degree, and he offers you a money-back guarantee. You might think "What a great deal" and accept.  But then again, you might start thinking "What a weirdo. What’s wrong with him?"  And this, I propose, is the stumbling block to lots of worthwhile innovations. A person with an unconventional idea may have a point, but is also unlikely to be "normal." He may not fit it with other people. He may have problems with authority. He may be deviant in more ways than one! 

The problem is that on average people who support odd ideas are less desirable as associates, and less discriminating in which ideas they endorse.  If people only endorsed odd ideas when they had new information suggesting such ideas were promising, we should be eager to hear of such news, and eager to associate with such people.  But in fact the main task faced by those with good news on odd ideas is to distinguish themselves from freethinkers who just pretend to have such news.  Contrary to their self-image, undiscriminating freethinkers are our main obstacle to innovation.