This study explored the use of Garrison, Anderson, and Archer's (2000) version of Dewey's (1933) practical inquiry model for assessing the influence of social presence and teaching presence on the quality of critical inquiry experienced by online learners. Students (N = 33) enrolled in an online version of a graduate-level, educational statistics course were randomly assigned to either a control, social presence, or social presence combined with teaching presence experimental discussion group. Results showed that the social presence combined with teaching presence group posted significantly more responses at the highest levels of cognitive presence than either the control or the social presence discussion groups.