In this statement, Tyson is referring to science as an objective reality. Science in human terms, as he often admits, has flaws that need to be explored and solved. However, in this quote, I understood him to be describing the pursuit of the objective truth, which is the primary mission of science in the first place. Scientists believe in an objective reality that can be described by thorough investigation and experimentation. Over the long-term, human science asymptotically approaches the truth, and to that truth, Tyson's statement refers.