I view it as meaning that as our science and tools have evolved, the more ability we have to affect our environment. Therefore the more we learn about relevant subjects, the better equipped we are to direct the future. I understand what your "90%" saying is getting at, but considering our reactions are completely dependent on our total subjective experiences, what happens to us is of much greater influence than 10% (I'd say 50-100% depending on if you mean "life" in a personal or general way). As for your last question, the best way to react to something unknown would be to learn as much as you can about it until it becomes more known, so you can act more accordingly to reality (science in a nutshell). We should try a hangout; look for me online.