philosophy 100

plato (427-347)

wrote dialogues of love, virtue, justice, piety, etc. socrates’ student, aristotle’s teacher

charges against socrates

studies things in the heavens and below the earth, makes the weaker reason appear stronger, corrupts the youth, and does not believe in the gods of the state

socrates’ defense

says he is wise in the sense of he doesn’t pretend to know what he doesn’t (socratic wisdom)

the value of critical thinking

makes us better, freer people

argument structure

premise 1

premise 2 (inference connects)

conclusion

good arguments

rationally persuasive arguments

deductive argument

an argument that is supposed to give logically conclusive support for its conclusive

inductive argument

an argument that is supposed to give probable support for its conclusion

validity

an argument is valid if it satisfies the following condition: if the premises were true, then the conclusion would have to be true. valid arguments needn’t have true premises. (if p, then q = p, therefore q)

soundness

an argument is sound just in case it’s valid and all of its premises are true

invalid argument

invalid and unsound

valid argument with true premises

valid and sound

valid argument with untrue premises

valid and unsound

deductive argument

an argument that is supposed to give logically conclusive support for its conclusion

inductive argument

an argument that is supposed to give probable support for its conclusion

deductive standards

valid vs invalid; all or nothing

inductive standards

strong vs weak; comes in degrees

enumerative induction

reasoning from a premise about a sample to a conclusion about an entire group; 70% of americans polled think X, so 70% of americans think X

inference to the best explanation

reasoning from premises about a state of affairs to an explanation for that state of affairs: explanation E best explains Q, so E is probably true

necessary condition

A is necessary for B if B cannot occur without A

sufficient condition

A is sufficient for B if the occur fe of A guarantees the occurrence of B

existing in the mind

X exists in the mind = we can think about X

existing in reality

X exists in reality = X exists

contingent

a contingent thing exists but might not have existed

impossible

an impossible thing couldn’t possibly exist

necessary

necessary thing exists and couldn’t have failed to exist

reductio ad absurdum - reduction to absurdity

an argument that attempts to prove a claim by showing that its denial leads to absurdity

st. anselm’s definition of god

the being than which none greater is possible

ontological argument

god exists in the mine, might exist in reality. it is false that gos exists only in the mind, he exists in both mind and reality.

gaunilo’s reply

the lost island = the island than which none greater is possible, substitute “lost island” for “god” and we can prove the lost island exists.

moral evil

evil caused by human choices

natural evil

evil out of our control (natural disasters)

the problem of evil

god is omnipotent and omnibenevolent but evil exists

evil is an illusion

if we could see the world as it is, we’d see that evil doesn’t exist

god has a higher morality we can’t understand

since we are not god, we see things as evil

theodicy

attempt to explain why god would allow evil

swinburne on moral evil

free will theodicy: we have free will and free will outweighs evil

swinburne on natural evil

suffering from natural evil makes possible virtues outweigh natural evil