Religion and Theology
Russell's ethical outlook and his personal courage in facing controversies were certainly informed by his religious upbringing, principally by his paternal grandmother who instructed him with the Biblical injunction, "Thou shalt not follow a multitude to do evil", something he says influenced him throughout his life.
For most of his adult life, however, Russell thought it very unlikely that there was a God, and he maintained that religion is little more than superstition and, despite any positive effects that religion might have, it is largely harmful to people. He believed religion and the religious outlook (he considered communism and other systematic ideologies to be species of religion) serve to impede knowledge, foster fear and dependency, and are responsible for much of the war, oppression, and misery that have beset the world.
In his 1949 speech, "Am I an Atheist or an Agnostic?", Russell expressed his difficulty over whether to call himself an atheist or an agnostic:
As a philosopher, if I were speaking to a purely philosophic audience I should say that I ought to describe myself as an Agnostic, because I do not think that there is a conclusive argument by which one can prove that there is not a God. On the other hand, if I am to convey the right impression to the ordinary man in the street I think that I ought to say that I am an Atheist, because, when I say that I cannot prove that there is not a God, I ought to add equally that I cannot prove that there are not the Homeric gods.
Though he would later question God's existence, he fully accepted the ontological argument during his undergraduate years,:
I remember the precise moment, one day in 1894, as I was walking along Trinity Lane [at Cambridge University where Russell was a student], when I saw in a flash (or thought I saw) that the ontological argument is valid. I had gone out to buy a tin of tobacco; on my way back, I suddenly threw it up in the air, and exclaimed as I caught it: "Great Scott, the ontological argument is sound!"
This quote has been used by many theologians over the years, such as by Louis Pojman in his Philosophy of Religion, who wish for readers to believe that even a well-known atheist-philosopher supports this particular argument for God's existence.
Russell also made an influential analysis of the omphalos hypothesis enunciated by Philip Henry Gosse—that any argument suggesting that the world was created as if it were already in motion could just as easily make it a few minutes old as a few thousand years:
There is no logical impossibility in the hypothesis that the world sprang into being five minutes ago, exactly as it then was, with a population that "remembered" a wholly unreal past. There is no logically necessary connection between events at different times; therefore nothing that is happening now or will happen in the future can disprove the hypothesis that the world began five minutes ago.
As a young man, Russell had a decidedly religious bent, himself, as is evident in his early Platonism. He longed for eternal truths, as he makes clear in his famous essay, "A Free Man's Worship", widely regarded as a masterpiece of prose, but a work that Russell came to dislike. While he rejected the supernatural, he freely admitted that he yearned for a deeper meaning to life.
Russell's views on religion can be found in his popular book, Why I Am Not a Christian and Other Essays on Religion and Related Subjects. Its title essay was a talk given on March 6, 1927 at Battersea Town Hall, under the auspices of the South London Branch of the National Secular Society, UK, and published later that year as a pamphlet. The book also contains other essays in which Russell considers a number of logical arguments for the existence of God, including the first cause argument, the natural-law argument, the argument from design, and moral arguments. He also discusses specifics about Christian theology.
Religion is based, I think, primarily and mainly upon fear. It is partly the terror of the unknown and partly, as I have said, the wish to feel that you have a kind of elder brother who will stand by you in all your troubles and disputes. […] A good world needs knowledge, kindliness, and courage; it does not need a regretful hankering after the past or a fettering of the free intelligence by the words uttered long ago by ignorant men.