Renewal of Science for the Public Good
I am optimistic that after almost 30 years of sensory deprivation in the field of particle physics, during which much hallucination (eg. string theory) has occurred by theorists, within 3 years, following the commissioning next year of the Large Hadron Collider in Geneva, we will finally obtain empirical data that will drive forward our understanding of the fundamental structure of nature, its forces, and of space and time.
My biggest optimism is that the data will be completely unexpected, forcing revisions in all our carefully prepared ideas about what will supplant the Standard Model of elementary particle physics. Since 1975 or so, every single experiment done at the microscopic forefront has been consistent with the predictions of the Standard Model, giving little or no direction to what lies behind it, what is the origin of mass, why there are three families of elementary particles, why some quarks are heavy, and why neutrinos are very light.
Yes, neutrino masses were discovered, but that was no big surprise, and no insight at all into their origin has been obtained thus far. With empirical data, theoretical particle physics might once return to the days when the key to distinguishing good theory from bad was how many empirical puzzles the theory might resolve, rather than how fancy it might look.
I am also completely optimistic that within what I hope will be my lifetime we will unlock the secret of life, and finally take our understanding of evolutionary biology back to that remarkable transition from non-biological chemistry to biology. Not only will we be able to create life in the laboratory, but we will be able to trace our own origins back, and gain insight into the remarkable question of how much life there is in the universe. We will surely discover microbial life elsewhere in our solar system, and I expect we will find that it is our cousin, from the same seed, if you will, rather than being truly alien. But all of this will make living even more fascinating.