In his early years, Russell adhered to Bradley's idealism. Then he went on to a platonic realism. Russell said that he began to believe in everything the Hegelians did not believe, which provided him with a plethorical Universe:
“ I imagined all the numbers sitting in a row in a platonic sky. He thought that the points in space and the moments of time were actually existing entities, and that matter might well be composed of real elements such as physics considers it convenient. I believed in a world of universal, consisting mainly of what is meant by verbs and propositions.” The evolution of my philosophical thought, Russell
But later, Russell will reach a ralism of “common sense” even without completely abandoning Platonic realism.
Russell's best known doctrines were thus:
It denies the persistence or substance of things. But this is a realistic constructionism, because the apparent persistence of things is the product of a construction of momentary and fleeting sensitive (real) data. The manther is not without “logical construction” of unstable, momentary and successive “particular” (corpuscles of time and space). It could be said that this construction resembles film production.
Atomist logic assumes that the world is composed of independent and isolated entities, which can be known without reference to the rest of the universe, directly in themselves. The basic idea of logical atomism is that the world possesses the structure of mathematical logic.
Russell argues that the substance of the world is not spiritual or material but a more neutral and primitive substance that sustains both. What constitutes the world are “events” and no longer “sense data” and from what perspective they are considered we find what is commonly called “matter” or “mind”.
And finally, Russell wrote a lot of small works in which he will deal with his piety for the sufferings of mankind and his desire to fight for freedom and justice.