However, the Scholars in the Irish college in Prague where Toland studied for a while, wrote him a testament in Latin claiming he came from a noble Gaelic family. At the age of 16 Toland converted to Protestantism. He received a thorough grounding in Theology, Greek and Latin in Londonderry before departing for university studies in Glasgow and Edinburgh, where he received a Master of Arts in 1690.
Toland continued his studies in Holland at Leiden University, at the time, a bastion of liberal thinking founded by William of Orange. In Holland, O Tuathaláin frequented the coffee-houses and taverns meeting all the greatest minds of his day. It was here that he came across the works of the Dutch philosopher Spinoza, whose radical ideas were to have a profound effect on his subsequent writing.
Having imbibed the liberal intellectual spirit of Holland, Toland went to Oxford where he read the philosophy of John Locke. Locke had argued that there was no contradiction between reason and religious faith. Toland decided to test this idea through a thorough examination of the Bible. The result was a book that would send shock-waves throughout Europe. 'Christianity Not Mysterious; or, A treatise Shewing That There Is Nothing in the Gospel Contrary to Reason, nor above It, and That No Christian Doctrine Can Be Properly Call'd a Mystery'.
Toland’s book asserted that Christianity did not contain any mysteries. These so –called mysteries, he argued, had been invented by priests to frighten and hoodwink the ignorant. Christianity Not Mysterious proved to be a best-seller throughout Europe. Its radicalism was such that it provoked over 50 separate publications attempting to refute its ideas.
The Irish parliament immediately ordered Toland's book to be burned and sent out a warrant for the author’s arrest. Toland fled to Oxford, where he would remain for a number of years. But it wasn’t long before the Gaelic philosopher would be the source of controversy yet again. In 1698 he published his monumental biography of the poet John Milton, where certain passages casting doubt about the authenticity of the New Testament caused outrage. However, his work Anglia Libera, which argued in favour of the Hanover succession, won him favour among the British authorities. He was employed by the British government as a foreign diplomat, frequenting the Court of Prussia, where he greatly impressed the Princess Sophia.
Toland also corresponded with the German philosopher Gotfried Leibniz, whose letters reveal a deep admiration for Toland’s genius mixed with a degree of reservation concerning his radical anti-religious views. Toland’s conversations with Princess Sophia resulted in a book entitled ‘Letters to Serena’ where he argued that motion was an intrinsic quality of matter, thus refuting the Cartesian conception of the world.
Toland’s writings are said to be in the range of 30 to 100 books and pamphlets. He was the first thinker to argue for the naturalisation of the Jews in Europe. During the course of his career Toland became increasingly atheistic. His opposition to established religion was argued in his book 'On Christianity, Judaism and Islam', three religions which he described as the three 'great frauds of humanity'. However, his magnum opus is generally considered to be his book written in Latin entitled Pantheisticon. Combining many ideas from Ancient Greek and Roman authors, this work proposed the concept of pantheism, which means that God and nature are one, and that the study of nature is the only true knowledge.
Toland’s works so obsessed the French philosopher Le Baron D’Holbach, the first confessed atheist, that his friend Denis Diderot, described its reception among the French intelligentsia as being like a bomb! D’Holbach immediately undertook the translation of some of Toland’s works into French. The French philospher's library contained all of Toland's published works. Diderot and Voltaire read the Irish philosopher with devotion. Toland also undertook a number of significant translations, the most important of which were works from the Italian philosopher Giordano Bruno.
Later in Life, Toland, who spoke over 10 languages, turned again to his native Irish. He studied documents pertaining to the Celtic languages in Oxford and tried to show that the Ancient Order of the Druids represented a more primitive form of his own thinking. He is also said to have translated part of the Gaelic historian Seathrún Céitinn’s Foras Feasa ar Éireann.
Described by eighteenth century Irish philosopher George Berkeley as the 'first free thinker', and by Johnathon Swift as the ‘oracle of the anti-Christians’, this Gaelic, British, European, republican, cosmopolitan genius has, with the exception of a few scholars, has been hitherto ignored by the Irish intellectual establishment. However, new editions of his works have recently appeared in France, where he has even been compared to Nietszche and Marx, while Italian scholars have been studying his works for over fifty years with many scholarly tomes emphasising the influence of Tolandian ideas on European thought.
Seán Ó Tuathaláin is arguably one of the greatest geniuses Ireland has ever produced. His overwhelming erudition and the radicalism of his ideas make him a man centuries ahead of his time and as the French scholar Albert Lontoine has noted, 'dangerous for his epoch'. But how could a philosopher of such importance still remain unknown in Ireland? That is perhaps a question best asked of the Catholic Church, who controlled our philosophy departments for decades since Irish independence, stifling intellectual debate with obsequious Thomism and pious medievalism, the kind of 'priestcraft' Toland spent much of his life denouncing.