I consider myself a scientifically minded person. After giving having a crisis of faith at the age of 18, I would have described myself as a materialist. I became interested in and studied philosophy in college. This study may have caused me to back-pedal a bit on holding materialism as a definitive metaphysical position, but I would still say my basic belief is that there is an objective reality “out there” that is independent of my or anyone else's opinion about it. I hold science in high regard and believe that it is capable of establishing the truth of statements about reality.
Various philosophical traditions have cast doubt on both the objective nature of reality and more specifically on the ability of science to escape the trap of politics and petty human biases. These traditions go too far in their skepticism in many cases. There is, however, an area in which I think they reveal a weakness in my own thinking as I have held it in the past.
I still believe that there are facts we can know with a great degree of certainty, like the boiling point of water. However, when it comes to questions of people and what they are capable of, I think that it makes sense to speak of subjective reality. Simply stated, believing that you are capable of doing something will make it true. One of the most obvious examples of this I can think of is lifting weights at the gym. If you are in sort of a blah mood, you might max out at say 10 reps. But on another day if you are in a great mood you might rip off 15 reps without even realizing it. Your attitude determined your capability.
Now obviously, this isn't positive thinking bending reality on the scale of Neo flying or stopping bullets in the Matrix. I guess I still believe there is a spoon, damn it. What I'm talking about is realizing what dynamic, amazing things we humans are. I think there is a tendency for people with a very logical and scientific viewpoint to forget this. They say things like “people are X”, or “I can't do that because I'm Y.” They treat human beings as if they were predictable, idealized billiard balls in a physics problem.
Of course, this sort of thinking is so pernicious because it is precisely the sort of thinking that creates its own reality for the person that believes it. Psychology reveals that people have a natural bias to confirm their own beliefs while ignoring evidence that casts doubts on those beliefs. This is a perfectly natural and healthy thing. You wouldn't have time to do anything else in your life if you were constantly having to re-evaluate all of your beliefs. The dark side of this is that it can create a feedback loop around negative beliefs like “people are lazy” or “I can't do math”, causing to continuously notice evidence that strengthen those beliefs while ignoring indications that they actually aren't objectively true, and are in fact actively harmful to ourselves and others.
So while the empirical method of science works, we as individuals tend not to be very good empiricists. It takes an active awareness of your beliefs and your own biases to ensure that the things you believe have a solid basis in reality. This isn't just a high minded appeal to positive thinking or combating bias. Very basic matters of quality of life like happiness are directly linked to the beliefs you hold, and the actions(or inactions) those beliefs engender.