The Liberal creed, in practice, is one of live-and-let-live, of toleration and freedom so far as public order permits, of moderation and absence of fanaticism in political programmes. Even democracy, when it becomes fanatical, as it did among Rousseau's disciples in the French Revolution, ceases to be Liberal; indeed, a fanatical belief in democracy makes democratic institutions impossible, as appeared in England under Cromwell and France under Robespierre. The genuine Liberal does not say, 'this is true,' he says 'I am inclined to think that under present circumstances this opinion is probably the best.' . . .Note that there is an important distinction between what Russell describes as 'Liberalism' and the opinions that are at the moment considered to be liberal in the U.S. If, say, you believe so strongly in predictions of climate change that you think opponents ought to be silenced as "denialists," you are not a Liberal in Russell's terms. Only polite disagreement is acceptable, unless the other side shoots first.
The essence of the Liberal outlook lies not in what opinions are held, but in how they are held: instead of being held dogmatically, they are held tentatively, and with a consciousness that new evidence may at any moment lead to their abandonment. This is the way in which opinions are held in science, as opposed to the way in which they are held in theology. The decisions of the Council of Nicaea are still authoritative, but in science fourth-century opinions no longer carry any weight. In the USSR the dicta of Marx on dialectical materialism are so unquestioned that they help to determine the views of geneticists on how to obtain the best breed of wheat, though elsewhere it is thought that experiment is the right way to study such problems. Science is empirical, tentative, and undogmatic; all immutable dogma is unscientific. The scientific outlook, accordingly, is the intellectual counterpart of what is, in the practical sphere, the outlook of Liberalism.
Locke, who first developed in detail the empiricist theory of knowledge, preached also religious toleration, representative institutions, and the limitation of governmental power by the system of checks and balances. Few of his doctrines were new, but he developed them in a weighty manner at just the moment when the English government was prepared to accept them. Like the other men of 1688, he was only reluctantly a rebel, and he disliked anarchy as much as he disliked despotism. Both in intellectual and practical matters he stood for order without authority; this might be taken as the motto both of science and of Liberalism. In the intellectual world it involves standards of evidence which, after adequate discussion, will lead to a measure of agreement among experts. In the practical world it involves submission to the majority after all parties have had an opportunity to state their case.
--Philosophy and Politics (1947)
And while I am on the subject of Bertrand Russell, let me offer my favorite saying of his:
Time you enjoy wasting is not wasted time.