He was Professor of Philosophy at the Residential College of the University of Michigan, in Ann Arbor, Michigan, U.S. Cohen was co-author of The Animal Rights Debate (Rowman and Littlefield, 2001),[1] a point-counterpoint volume with Tom Regan; he is also the author of Democracy (Macmillan, 1972); the author of Four Systems (Random House, 1982); the editor of Communism, Fascism, and Democracy (McGraw Hill, 1997); the co-author (with J. Sterba) of Affirmative Action and Racial Preference (Oxford, 2003), co-author (with I. M. Copi) of Introduction to Logic, 13th edition (Prentice-Hall, 2008), and author of A Conflict of Principles: The Battle over Affirmative Action at the University of Michigan (University Press of Kansas, 2014).

From 1964 to 1967, Cohen, then an Associate Prof. of Philosophy, was an active member of the small planning committee for the Residential College of the University of Michigan.

Barbara Grutter, in a separate proceeding, sued the Law School of the University of Michigan relying on additional data also revealed by Cohen's FOIA inquiry.

As a result of Cohen's involvement in the issue, he has appeared on numerous panels and in media reports on racial preferences since the mid-1990s.

When the American Nazi Party threatened, in 1978, to march in Skokie, Illinois, Cohen published (in The Nation to which he was a regular contributor) several widely reprinted essays defending the right to present publicly even the most abhorrent political views.

[3] When (as a part of the protest against the Vietnam War) efforts were made to forbid research of certain kinds on the U-M campus, Cohen strongly supported the freedom of faculty members to engage in the inquiries that they thought appropriate.

[7] From 1985 to 1995 a fraction of Cohen's appointment was in the Medical School of the University of Michigan, where he served as Professor of Philosophy and as Director of the Program in Human Values in Medicine.