 Suppes (1970) independently offered an equivalent definition of causation, although his motivation for the no-screening-off condition was different from Reichenbach’s. Suppes extended the framework in a number of directions. While Reichenbach was interested in probabilistic causation primarily in connection with issues that arise within the foundations of statistical mechanics, Suppes was interested in defining causation within the framework of probabilistic models of scientific theories. For example, Suppes offers an extended discussion of causation in the context of psychological models of learning.