Clarke studied scripture in the original languages, and the primitive Christian writers. He took the degree of doctor in divinity in 1710, defending as his thesis the two propositions: "Nullum fidei Christianae dogma, in Sacris Scripturis traditum, est rectae rationi dissentaneum", and "Sine actionum humanarum libertate nulla potest esse religio". The formal disputation was long remembered for Clarke's virtuosity; but the presiding Regius Professor, Henry James, received the distinct impression that Clarke's views on the Trinity were unorthodox. Clarke was required to swear to keep the 39 Articles; and his attempt at self-justification by putting his views in book form were not immediately successful.