Relativism

Wickedness by Mary Midgley

Divine Command Theory

Does Good Need God Roy Jackson

Kantian Duty, Free Will, Deontolgy

Utilitarianism

The Utilitarian Horrors of Peter Singer by Peter Berkowitz

Contractarianism

John Rawls and the Liberal Faith a critique by Peter Berkowitz

The Culture of Citizenship: Inventing Postmodern Civic Culture - a book by Tom Bridges

Pragmatism

Returning to Reason Reasonably a review by Peter Berkowitz

Pluralism

Berlin's Big Idea by Herny Hardy (pluralism)

Value Pluralism and Political Liberalism by William A. Galston

In Defense of Enlightenment Liberalism: A Reply to William Galston

After Autonomy a review of Value Pluralism by Peter Berkowitz

Causuistry

Causuistry by Peter Holmes

Axiology

Socrates and Plato

Commentary on Plato's Apology of Socrates  by Kelly L. Ross

Commentary on the Euthyphro by Kelly L. Ross (polemical)

Commentary on the Meno, Part 1  by Michael Sudduth

Commentary on the Meno, Part 2  by Michael Sudduth

Commentary on the Crito Jowett's Introduction

Commentary on Gorgias Jowett's Introduction

Commentary on Protagoras Jowett's Introduction

The 'Simonides Agon' as a Pivotal Discourse in Plato's Protagoras Vernon Provencal Acadia University

Embodied Perspective vs. Objective Measurement: Rationality in Plato's Protagoras Tim Rohrer U of Oregon

The Project of Self-Education in Plato’s Protagoras, Gorgias, and Meno  Jeffrey S. Turner Bucknell University

Commentary on Philebus  Jowett's Introduction

The Ring of Gyges and the Myth of the Cave Bernard Suzanne

Aristotle

Aristotle on the Good Life Michael Sudduth 

Aristotle's Political Virtues Edward Halper University of Georgia

Ethics and Community in Aristotle May Sim Oklahoma State 

Augustine

Augustine and Boethius: God, Freedom, and Foreknowledge Michael Sudduth

Aquinas

Aquinas snapshot

Meaning of Virtue in Thomas Aquinas by Fr. John A. Hardon, S.J.

Thomas Aquinas and Augustine Medieval Ethics by G. J. Mattey's

Pico

Locke

Hume

Hume and Morality by James Braille

Kant

On whether there is moral worth only in actions done from the motive of duty:

• Judith Baker, "Do One's Motives have to be Pure?" in Richard E. Grandy & Richard Warner, eds., Philosophical Grounds of Rationality: Intentions, Categories, Ends (Clarendon, 1986)
• Paul Guyer, "Duty and Inclination" chapter 10 of Kant and the Experience of Freedom (Cambridge, 1993), especially section I
• Marcia Baron, "The Alleged Moral Repugnance of Acting from Duty" The Journal of Philosophy 81 (1984) [more on arguments about the issue than about interpretation of Kant as such]

• Mark Timmons, "Kant's Strategy in the Ethical Works: The Construction of a Rationalist Internalism" Southwest Philosophical Studies 8#1 (1982) pp. 103-111

Kant and the Project of Enlightenment  by Curtis Bowman

John Stuart Mill

Mill snapshot

Hegel

Nietzsche

Darwin

Freud

Sartre

Sartre's Existential Humanism Part 2 by Jeff Mason

Berlin

Rawls

Rorty

Taylor