Phi Sigma Tau is the International Honor Society in Philosophy. Founded in 1930 and incorporated as a nonprofit corporation in 1955, the Society now has a network of over 200 chapters throughout the United States and Canada, at both public and private institutions of higher learning. The purpose of Phi Sigma Tau is to encourage interest and activity among students and to promote ties between philosophy departments in accredited institutions. Phi Sigma Tau publishes a journal, Dialogue, for student contributions in all areas of contemporary philosophical research. Other PST publications include the PST Newsletter (published three times yearly) and the National Alumni Chapter Bulletin. The PST Newsletter is sent to all students and alumni/ae members and contains news of local chapter activities. The National Alumni Chapter (NAC) provides a medium of exchange and communication for onetime PST members who desire to retain their affiliation with the Society following graduation.

The nearly seventy honor societies which make up the Association of College Honor Societies (ACHS) are as divergent as knowledge itself. From forestry to physics, from highly specialized to general areas, these member organizations exist for one basic purpose — to further scholarship and achievement in the academic areas of their members, thereby providing a forum where interested and competent students may communicate and exchange ideas with faculty and students of similar interest on their own campus and throughout the world.

Dr. Everett Fulmer is the faculty advisor to Loyola's branch of PST.