Experience failure, and learn how to recover

"Mistakes are made in research, science, analysis, data collection, assumptions, etc for any number of reasons. Many people have asked how we can prevent such mistakes from happening. Today, at the end of class, I asked you a different question. What if we accept that mistakes will be made and might even be unavoidable? Are there ways that we, as a society or research community, can avoid getting trapped into following wrong directions by those inevitable mistakes?"

There's nothing that we as humans can do to prevent all mistakes. This is especially pertinent to research, because there is no one around to check our answers and say we got it right--we have to rely on other humans to check our work and say "Yeah, that looks okay to me." That's just how it is, and there's not much we can do in that respect besides just accept it wholeheartedly.
If being wrong was more socially acceptable in the scientific community and the media, people might be more comfortable confessing mistakes and starting over, without risk to their reputation if the mistakes were indeed honest and accidental. However, this is easier said than done, because as in the case of Potti, et al., sometimes being wrong costs lives.
Scientists need to start entering the field with less of an expectation of curing cancer, and more of an expectation of trying to help cure cancer. These new scientists might be so used to academic success that it's jarring when something they do actually fails. In addition, as mentioned in class, the pressure to advance professionally and publish, publish, publish in journals probably contributes to the fear of uninteresting, un-groundbreaking results. Even if the alternative hypothesis should be rejected, it's still a better read than "nothing happened."
As a society, we would have to do a couple things: 1. Stop with the tiger-mom culture of pushing your kids to extreme excellence, at the cost of normal life, friendships, and important experiences like failure, and recovery from failure. 2. Get the media and general public to stop treating scholarly journal articles as holy grails of current knowledge, and more like the being-reviewed works in progress that they are.
Maybe if these cultural shifts actually happened, people would collaborate more on these works of progress for the sake of science, and not a career; be less blind to any imperfections in one's own work; and be more open to mistakes happening and being fixed, without risk of a public shaming.