Harvard University: Michael Sandel's "The Supreme Principle of Morality"
Watch this lecture from 28:26 to the end. Pay attention to the distinction Sandel draws between hypothetical and categorical imperatives, since this is what sets Kant apart from the utilitarians. Sandel helpfully breaks down some of the complexity of Kant's moral philosophy by illustrating the major contrasts that Kant uses to develop it. Although he gives three different versions of it, Kant thinks of his categorical imperative as a singular rational principle for deciding how to act. As long as we follow the categorical imperative, we are acting out of duty, and we are respecting ourselves and others as rational beings.
Click http://theopenacademy.com/content/lecture-6-mind-your-motive link to open resource.