There are those philosophers and historians of science who claim that the acceptance and rejection of scientific theories is underdetermined by experimental results. They conclude that there is no rational method for deciding such matters solely on the basis of empirical information. The acceptance and rejection of scientific theories depends on social influence and is settled by social dominance. This I call the dominance thesis. There are also those who hold, on the contrary, that the acceptance and rejection of theories (...) in science is based solely on empirical information according to a rational method. They conclude that the acceptance and rejection of scientific theories is fully determined by experimental results. This I call the experimentalism thesis. The dominance thesis and the experimentalism thesis are both false. Both share a common premise, to wit, that empirical information is limited to experimental results. There is, however, another source of empirical information, the opinions of experts. When such social information is properly aggregated, the acceptance and rejection of scientific theories, though underdetermined by experimental results, is fully determined by the total information available. (shrink)