 On the other hand, Moore (1978) considers the programs-as-theories thesis another myth of computer science. As programs can only simulate some set of empirical phenomena, at most they play the role of computational models of those phenomena. Moore notices that for programs to be acknowledged as models, semantic functions are nevertheless needed to interpret the empirical system being simulated. However, the view that programs are models should not be mistaken for the definition of programs as theories: theories explain and predict the empirical phenomena simulated by models, while simulation by programs does not offer that.