February 18, 2008 Kant principles handout page 1
fundamental question in ethics is, “Why should I do the right thing?” Suppose you show
someone that giving to charity is the right thing to do. What if the person says, “So what? I think I
would like to do the wrong thing. What do I care whether what I do is right or wrong?”
In very broad outline, Plato’s conception of ethics was the following: There is an objective
Good, which is part of the natural order, that is, the structure of the world. The good life for human
beings, and right ethical behavior, is living in accordance with this objective Good. The human
good, the good of the “essential human,” the soul is objectively well-off to the extent that its
actions are in accord with this Good.
Consider two issues about the good life:
1) What is the objective basis for the goodness of the good life? Plato answers this question by a
metaphysics that makes Goodness part of the structure of the universe.
2) How can you convince a person to do the right thing, to live in accord with justice? Plato’s
strategy is to try to establish that doing the right thing is in a person’s best interests. The idea is that
everyone naturally tries to act in their own best interests, so, if Plato can show that doing the right
thing coincides with acting in your own interests, he will have a convincing argument.
Unfortunately, for that argument to work in every case, even in extreme situations in which
a person is threatened with death if the person does the right thing, Plato requires that there be an
afterlife. Also, Plato requires a metaphysical background which could be doubted.
There is another way to try to show that a person ought to do the right thing. If you could
show that a person who does wrong things is acting irrationally, you would show that a person
logically ought to do the right thing. This would treat the “ought” of ethics as the “ought” of logic
and math. That is, just as you ought to believe that if it is raining and cold, then it is raining, so you
ought to act in the right way. The right way to act will fall out of an analysis of what it is to act on
purpose, just as the reasonableness of believing a logical truth falls out of the analysis of what it is
to believe. In both cases, action and belief, rationality, that is, logic, requires coherence.
So, this strategy tries to establish that acting wrongly is incoherent, irrational. Kant is the
paradigm example of this strategy for showing that a person ought to do the right thing.
I Introduction: Ethical Principles
II Who Kant is;
Kant’s general project in Metaphysics:
III Kant’s Project in Ethics
A) Kant on the TRUTH question
B) Kant on the MOTIVATION question
I Ethical Principles
Historically, the model for how ethical thinking reaches conclusions has pictured ethics as a
system of universal laws or principles. The ethical principles are applied by a more or less
deductive procedure: given a situation, the principle tell you what the right thing to do is in that