Realism, generally, is the view according to which knowledge refers to objects that actually exist. Hypothetical realism is a weak form of realism based on the theory of the growth of knowledge put forward by evolutionary epistemology. The basic assumption is that human cognitive capacity has evolved through an interaction with the external world. Therefore even if our knowledge has only a hypothetical character and must be open to improvements, the ontological reality of the known (i.e., external reality) is certain.
See also Critical Realism; Evolutionary Epistemology; Realism