{ 1 } - that truth claims (except for analytic ones) must be empirically verifiable.
{ 2 } - that only matter exists.
{ 3 } - an optimistic and logical attitude toward life.
{ 4 } - that logic can prove that things have positive value.

Logical positivism is a view about which statements are cognitively meaningful (in the sense of being true or false).

This view was popular once, but it isn't today. There are good reasons for this loss of popularity. For one thing, the view itself isn't analytic or empirically verifiable -- and so is meaningless on its own terms.