zeitgeist and science

There is a lot of room for speculation and bias in science. What is ruled out by experiments is much smaller compared to what is being written and talked about. 

Scientists, just like everyone else, are moved by the spirit of their times. Hence the reason why we see swings in the generally accepted interpretations of complex hot topics. 

For instance, when the future looks bleak and unpredictable, we lean towards non-deterministic theories that bar us from making accurate predictions. (That is essentially why non-deterministic interpretations of quantum physics were considered to be philosophically more sound than their deterministic counter parts.) In such times, we also start believing that nature plays a greater role than nurture in human development.