In 1989 Roger F. Gibson succeeded Professor Krukowski as Chair. He remained chair for 10 years. During his first years as chair the department underwent an external review, as a result of which many new appointments were made to the department.

Three of these appointments were of faculty primarily in value theory: Larry May (1991-present), Marilyn Ann Friedman (1991-present), and Jennifer Hawkins (1999-2001). Also in value theory, Joel Herbert Anderson was initially appointed as visiting instructor (1994-1997). In 1997 he was appointed to a combined appointment as Assitant Professor of Philopophy and Assistant Dean in the College of Arts and Sciences. Three were in history of philosophy: Eric Brown (1996) Hud Hudson (1991-1992)and Pauline Kleingeld (1993-present). One was in philosophy of language: Josefa Toribio Mateas (1993-2000).

Perhaps the major development of the 1990s was the creation of a new program in Philosophy-Neuroscience-Psychology, supported initially by a substantial grant from the James S. McDonnell Foundation. The following members of the PNP program were appointed during this period

1. Keith Lawrence Butler (1993-1996).
2. Andy Clark (1993-2000).
3. William Bechtel (1994-2002).
4. Jesse Prinz (1996-2003)

During the 1990s a number of faculty held visiting appointments.

1. James Buickerood (1990-1992 and 1999-2001).
2. Jay Graham Campbell (1992-1993).
3. Marc Ereshefsky (1989-1990).
4. George N. Georgacarakos (Fall 1992).
5. Jody L. Graham (1992-1993).
6. Ernest LePore (1990-1991).
7. Thomas Oberdan (1989-1990).
8. Robert Rafalko (1990-1991).
9. Clark Thompson (1990-1991).
10. Margaret Urban Walker (Spring 1994).

During the 1990s the PNP program began to appoint postdoctoral fellows. The following help such fellowships in the 1990s.

1. Irene Appelbaum (1995-1997)
2. David Chalmers (1993-1995)
3. Morten Christiansen (1995-1997)
4. Richard S. Grush (1995-1997)
5. Brian Keeley (1997-1999)