The above discussion related to the assessment of NOS conceptions raises an important issue in contemporary understandings of the field. There exists a growing concern that students may have more than one set of beliefs regarding NOS. Hogan (2000) suggests that students have both proximal and distal understandings of NOS. Students’ proximal understandings of NOS involve perceptions of their own personal involvement in the generation of science knowledge. Distal understandings refer to student conceptions of professional science. Hogan suggests that many NOS research interventions are insensitive to the potential differences between these two conceptions. These interventions may be influencing students proximal understandings of NOS, but assessments used to gauge their impact focus almost exclusively on measures of distal NOS understandings without providing opportunities for students to make explicit connections to their own participation in science. Hogan recommends that science education research make a distinction between distal and proximal NOS understandings and investigate each independently before attempting to examine their interrelations. Sandoval (2005) makes a similar argument when he suggests that students hold both practical and formal epistemologies of science. Practical epistemologies (like proximal understandings) are students’ ideas about their own inquiry and the knowledge creation it involves. Formal epistemologies (like distal understandings) are students’ beliefs about professional science. Unlike Hogan (2000), Sandoval suggests that science education research should examine both practical epistemologies and formal epistemologies simultaneously in an effort to understand how they are related to each other.