Much modern moral/ethical philosophy takes as its starting point the apparent variance between peoples and cultures regarding the ways they define what is considered to be appropriate/desirable/praiseworthy/valuable/good etc. (In other words, variance in how individuals, groups and societies define what is in accordance with their normative standards.) This has led philosophers such as A.J. Ayer and J.L. Mackie (for different reasons and in different ways) to cast doubt on the meaningfulness of normative statements.