 This aspect of knowledge claims from science is seen as extremely problematic for positivist scientists looking for explanations.However, scientists using a pragmatic paradigm respond to this concept in two ways; first by questioning the value of research carried out in a controlled situation (Brown 1992; Hodkinson 2004; Kelly and Lesh 2000; Perrin 2000; Susman and Evered 1978; Walker and Evers 1999; Zaritsky et al.2003) and secondly, by looking at causal effects through a different perspective.