Here is a brief sketch of the philosophical struggle that went on in Ireland over the ideas of the Enlightenment. It is based heavily on part II of David Berman’s Berkeley and Irish Philosophy. (“We Irish think otherwise” is a quote from Berkeley. All links in text are Wiki).
The signing of the Treaty of Limerick had marked the final defeat of the old Irish landowning classes. It also marked the end of wars that since 1642 had seen thousands killed, exiled and dispossessed.
Despite the turmoil, Ireland was not isolated from new ideas from Britain and Europe. William Molyneaux, a natural philosopher and founder of the Dublin Philosophical Society (1683) had given his name to Molyneaux’s Problem in his friend Locke’s Essay Concerning Human Understanding. Another interested in the new ideas was Robert Molesworth, a Whig, a follower of Lord Shaftsbury. Graduates from Trinity mingled with those from Oxford on the Dublin streets.
John Toland published Christianity Not Mysterious in 1696. Much as Augustinus Hibernicus before him had brought Augustine’s thought to a logical conclusion, Toland did the same with the ideas in Locke’s Essay. He argued that only intelligible ideas could be believed. There could be no religious mysteries, such ideas would have to be nonsense.
This position had both religious and political implications, potentially undermining faiths and the basis of the Penal Laws. Toland arrived in Dublin to hear himself and his book denounced from the pulpit. His book was condemned by the Irish government and he left the country to avoid arrest.
Philosophically, though, Toland’s contention needed an answer. In their efforts to create one the Irish Counter Enlightenment also used the ideas of Locke, and thereby triggered a philosophical programme which saw developments in epistemology, aesthetics, religion, ethics and language.