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James Rachels

Argues that different cultural rules do not prove the absence of objective moral truths.

Cultural Relativism

The belief that morality depends entirely on culture.

Moral mistakes according to Rachels

People can make moral mistakes even while following cultural beliefs.

Russ Shafer-Landau

Believes that objective moral truths exist, but we should remain humble.

Humble about morality

We could be mistaken even when we believe we are right.

Dogmatism

Being so certain of your beliefs that you refuse to consider being wrong.

J. L. Mackie’s problem of evil

An all-powerful, wholly good God seems incompatible with the existence of evil.

Mackie’s three claims

God is all-powerful; God is wholly good; evil exists.

Conflict in Mackie’s claims

A good God would want to remove evil, and an all-powerful God could remove it.

William Paley’s argument

Complex things working together for a purpose suggest an intelligent designer.

Paley's watch example

A watch whose parts work together to tell time, implying intelligent design in nature.

Premise

A statement supporting an argument’s conclusion.

Conclusion

The claim an argument is trying to prove.

Valid argument

If the premises were true, the conclusion would have to be true.

Sound argument

A valid argument with all true premises.

Invalid argument

The premises could be true while the conclusion is false.

Validity of arguments

A valid argument can have false premises; validity depends on logical structure.

Difference between valid and sound

Valid means the conclusion follows logically; sound means valid with true premises.

Modus Ponens

If P then Q. P. Therefore Q.

Stove example of Modus Ponens

If I touch the stove, I get burned. I touched it. Therefore I got burned.

Remembering Modus Ponens

Affirm the IF part to establish the THEN part.

Modus Tollens

If P then Q. Not Q. Therefore not P.

Stove example of Modus Tollens

If I touch the stove, I get burned. I did not get burned. Therefore I did not touch it.

Remembering Modus Tollens

Deny the THEN part, then deny the IF part.

Difference between Ponens and Tollens

Ponens affirms P; Tollens denies Q.

Affirming the consequent

The invalid argument: If P then Q. Q. Therefore P.

Aristotle’s three kinds of friendship

Usefulness, pleasure, and virtue.

Friendship of usefulness

Friendship based on what people can do for each other.

Friendship of pleasure

Friendship based on enjoyment and fun together.

Friendship of virtue

Good people wishing good for each other for the other’s sake.

Best friendship according to Aristotle

Friendship of virtue.

Living without friends according to Aristotle

Nobody would choose to live without friends, even with other good things.

True friendship definition for Aristotle

Mutually wishing good for each other for the other’s sake.

Wanderly's argument about love

Real love involves needing the other person.

Example used by Wanderly

A six-year space trip illustrating love involves missing and needing someone.

Difference between real love and thin love

Real love involves deeply needing and missing the person.

C. S. Lewis on friendship

Friends stand side by side, sharing interests and experiences.

Lewis on friendship vs. romantic love

Friends stand side by side; romantic lovers face each other.

Monogamy debate

Whether romantic exclusivity is necessary for a meaningful relationship.

Chalmers' argument against monogamy

Having more friends does not make each friendship less special.

Chalmers on loving qualities

If love depends only on qualities, an identical person should be equally lovable.

Question raised by Chalmers about love

Do we love people for their qualities or for who they uniquely are?

Socrates in the Apology

We should not assume death is bad because we do not know what it is like.

False wisdom according to Socrates

Fearing death as if we know it is terrible when we actually do not.

Socrates' two possibilities for death

Dreamless sleep or the soul traveling to meet people from the past.

Goodness of dreamless sleep

It could be peaceful and free from suffering.

Goodness of the soul’s journey

We could meet and speak with people from the past.

Socrates' argument in the Phaedo

Death separates the soul from the body.

Socrates' description of death in the Phaedo

The soul leaving the body and becoming free from bodily distractions.

Philosophy is practice for dying meaning

Philosophers practice separating thought from bodily desires to seek truth.

Difference between Apology and Phaedo

Apology emphasizes uncertainty; Phaedo emphasizes the soul leaving the body.

Ecclesiastes on death

Death comes to everyone regardless of wisdom or morality.

Who faces the same fate in Ecclesiastes

Wise and foolish, good and bad, humans and animals.

Ecclesiastes on the dead

The dead know nothing and receive no more earthly rewards.

Contrast of Ecclesiastes with Socrates

Socrates sees possible benefits in death; Ecclesiastes emphasizes its inevitability.

Main lesson of Ecclesiastes about death

Everyone eventually faces the same fate.