> why is the point go saying somhehting like i don"t just believe - i know it . Why is knowl. important? security, planning and building". > philo position which asserts that we have no knowl. > 3 diff ways we use the word know". Necessary cond: when (if x then y) is true then y is necessary condition for x (ex. oxygen is a nec. cond. for a match lighting, living in canada is a nec. cond for living in toronto) Suff cond: when (if x then y) is true then x is a suff. con for y (ex. living in toronto is suff cond. for living in canada) A perf def" gives both necessary and suf cient condition for something (ex. prime nuember is greater then 1 divisible only by 1 and itself) Every action can be explained in terms of 2 mental states - beliefs and desires.