Tractatus Wittgenstein came to study under Russell in 1912 and contributed to the theory of logical atomism. His Tractatus Logico-Philosophicus was published in 1921. In the Tractatus Wittgenstein put forward the picture theory of meaning. A picture may mirror reality by showing objects and arrangements of objects. Wittgenstein argued that sentences, if they are to mean anything, must mirror reality in the same way that a picture does.
Sentences contain names that refer to objects or states of affairs in the world.
Like Russell, Wittgenstein thought that the surface grammar of statements disguised their logical form. Through analysis a true statement would be shown to consist in elementary particles which pictured the world and logical constants such as 'if', 'not', 'and' and 'or'. A sentence, which did not picture the world, was devoid of meaning. If only statements which picture the world, i.e. statements about facts, are meaningful then statements about ethics, religion and much of philosophy are not, strictly speaking, meaningful. This applies as much to Wittgenstein's ideas in the Tractatus as other philosophical ideas.