1. Metaphysical materialism ↑
In 1796, French mathematician Pierre-Simon Laplace's nebular hypothesis explained how the Solar System formed without the need for divine intervention. The atomic theory of matter was developed by British chemist John Dalton in 1808, and British naturalist Charles Darwin's theory of evolution by natural selection, first published in 1859, removed the need for God in order to explain the creation of species[3a].
An intellectual movement arose in Germany called metaphysical materialism. Metaphysical materialists argue that nature is entirely self-regulating, that there is nothing but physical substances, and no need for God or mind-body dualism[4a].
2. Charles Darwin ↑
Darwin's The Origin of Species was particularly useful to materialists because it is incompatible with a literal reading of Genesis. Darwin's theory also added to a growing acceptance that the age of the Earth was far greater than the bible suggests[3b].
In 1871, Darwin's The Descent of Man, caused greater controversy by suggesting that people and apes probably evolved from the same ancestors. Aside from being morally unpalatable to some, this conflicts with the biblical description of the divine creation of Adam and Eve.
Darwin was never accused of materialism because he refused to talk about religious matters in public. He stated that:
"freedom of thought is best promoted by the gradual illumination of [people’s] minds, which follows from the advance of science. It has, therefore, been always my object to avoid writing on religion".
Darwin's religious views are found in his personal correspondence. When The Origin of Species was first published, he suggested that we should find relief in the fact that pain and suffering result from universal laws, rather than as a direct result of God.
A year after publication, Darwin supported British biologist Thomas Huxley's stance on religion, referring to Huxley's statement that "extinguished theologians lie about the cradle of every science as the strangled snakes of Hercules", as a "splendid" analogy.
Darwin also claimed that the argument from design, which suggests that God must exist as the universe appears to have been intelligently designed, might be false.
Darwin stated, "the more I think on the subject, the less I can see proof of design". He considered design arguments to be too selective, they could explain "the accumulated variations by which the beautifully adapted woodpecker has been formed" but had nothing to say about "each variation in the rock-pigeon", which "[people have] made by accumulation a pouter or fantail pigeon, as providentially designed for [people’s] amusement".
In 1871, Darwin also admitted reservations over the first cause argument for God. This is the argument that every event has a cause and so a being must exist that caused its own existence. Darwin stated, "I can never make up my mind how far an inward conviction that there must be some Creator or First Cause is really trustworthy evidence", but he still adamantly denied atheism.
In 1879, Darwin claimed:
"I have never been an atheist in the sense of denying the existence of a God - I think that generally (and more and more so as I grow older), but not always, that an agnostic would be the most correct description of my state of mind".
By 1880, Darwin's religious views had evolved to the point where he stated: "I do not believe in the Bible as a divine revelation, and therefore not in Jesus Christ as the son of God". Yet Darwin was never a materialist, he claimed to have once "received a German pamphlet about the idea of God and immortality and socialism under a Darwinian point of view" but found it "so difficult" that he could not "make head or tails of it".
3. John Tyndall ↑
Materialism caused controversy in the UK and Ireland when president of the British Association for the Advancement of Science (BAAS), Irish natural philosopher John Tyndall, used his 1874 annual address to defend science against the encroachment of the Church[13a].
Tyndall summarised the history of science starting with Democritus, the first atomist. He described Democritus' belief that "the only existing things are the atoms and empty space; all else is mere opinion", and that the "soul consists of fine, smooth, round atoms, like those of fire". He went on to discuss Copernicus, Bruno and Galileo, whose theories were all met with resistance from the Church[13b].
Tyndall stated that "matter" contains "the promise and potency of all terrestrial Life". He went on to attack the Church's role in science, claiming that "in relation to scientific culture" religion is "dangerous, nay destructive, to the dearest privileges of freemen"[13c].
The Church was offended and, for the first time, the press began to portray Tyndall as "aggressive, dishonest, devious, and distinctly un-British"[14a]. It was even suggested that he should be investigated for blasphemy, a crime that people were imprisoned for up until 1921 in the UK and Ireland, but nothing came of this accusation. Tyndall denied that he was advocating materialism but he did admit to making ambiguous claims that could easily be misinterpreted[14b].
The conflict was not purely intellectual, by the mid-1800s a group of scientists that included Tyndall, Huxley, and British polymath Francis Galton campaigned to separate science from religion. They called themselves 'the young guard' and quickly became a powerful influence, participating in the BAAS, the Royal Society, and the Philosophical Club. They helped establish Nature and formed the X-Club, a place for discussing science free from religious dogma. This was where Huxley first coined the term 'agnostic', devised to distance their views from those of atheists[4b].
Science education remained an area of conflict by the time of Tyndall's address. The Education Act of 1870 had lessened the Anglican influence on science education in the UK, but this had not yet happened in Ireland and the Catholic education still did not include science[4c].
Huxley described Roman Catholicism as their "great antagonist" and a "damnable perverter of mankind", and it was for these reasons that, when given the opportunity to perform his presidential address in Belfast, Tyndall chose to condemn the Church.