 Collins’ central passion is the autonomy of reason particularly with respect to religion. Collins was strongly motivated by an aversion to religious persecution. Issues revolving around religious freedom are the threads that run through all of his writing. It is possible to divide Collins’ works into those that are mainly philosophical and those that are more narrowly religious, but they are clearly connected. His 1707–8 pamphlet controversy with Samuel Clarke over whether “matter can think” and other topics, and his book about free will and determinism are chiefly engaged with philosophical topics. Even these topics, however, involve such religious issues as the immortality of the soul and punishment and reward in the next life. His writing about reason and free-thinking may be regarded as on the borderline between philosophy and religion. Although it deals with epistemological and sometimes metaphysical issues, it focuses almost entirely on religious issues. His religious works are even more narrowly focused. The Thirty-nine Articles are the only official confessional statement of Anglicanism. Two of Collins’ books deal with the authenticity of Article 20 of the Thirty-nine Articles and whether the church has the power to make doctrine. In large measure, these represent the doctrines of free-thinking applied to the particular case of the Anglican Church. Collins also wrote a book examining the question of whether the prophecies of Christ’s messiahship could be accepted. This seems to be a rejection of Christianity as a revealed religion. How far Collins went in the direction of atheism is still a matter of scholarly debate.