Joseph Priestley and Dissent - Materialist Philosopher and Theologian

Materialist Philosopher and Theologian

In a series of five major metaphysical works, all written between 1774 and 1778, Priestley laid out his materialist view of the world and tried "to defend Christianity by making its metaphysical framework more intelligible," even though such a position "entailed denial of free will and the soul." The first major work to address these issues was The Examination of Dr. Reid's Inquiry ... Dr. Beattie's Essay ... and Dr. Oswald's Appeal (1774). He challenged Scottish common-sense philosophy, which claimed that "common sense" trumped reason in matters of religion. Relying on Locke and Hartley's associationism, he argued strenuously against Reid's theory of mind and maintained that ideas did not have to resemble their referents in the world; ideas for Priestley were not pictures in the mind but rather causal associations. From these arguments, Priestley concluded that "ideas and objects must be of the same substance," a radically materialist view at the time. The book was popular and readers of all persuasions read it. Charles Lamb wrote to Samuel Taylor Coleridge, recommending "that clear, strong, humorous, most entertaining piece of reasoning" and Priestley heard rumors that even Hume had read the work and "declared that the manner of the work was proper, as the argument was unanswerable."

When arguing for materialism in his Examination Priestley strongly suggested that there was no mind-body duality. Such opinions shocked and angered many of his readers and reviewers who believed that for the soul to exist, there had be a mind-body duality. In order to clarify his position he wrote Disquisitions relating to Matter and Spirit (1777), which claimed that both "matter" and "force" are active, and therefore that objects in the world and the mind must be made of the same substance. Priestley also argued that discussing the soul was impossible because it is made of a divine substance and humanity cannot gain access to the divine. He therefore denied the materialism of the soul while simultaneously claiming its existence. Although he buttressed his arguments with familiar scholarship and ancient authorities, including scripture, he was labeled an atheist. At least a dozen hostile refutations of the work were published by 1782.

Priestley continued this series of arguments in The Doctrine of Philosophical Necessity Illustrated (1777); the text was designed as an "appendix" to the Disquisitions and "suggests that materialism and determinism are mutually supporting." Priestley explicitly stated that humans had no free will: "all things, past, present, and to come, are precisely what the Author of nature really intended them to be, and has made provision for." His notion of "philosophical necessity," which he was the first to claim was consonant with Christianity, at times resembles absolute determinism; it is based on his understanding of the natural world and theology: like the rest of nature, man's mind is subject to the laws of causation, but because a benevolent God has created these laws, Priestley argued, the world as a whole will eventually be perfected. He argued that the associations made in a person's mind were a necessary product of their lived experience because Hartley's theory of associationism was analogous to natural laws such as gravity. Priestley contends that his necessarianism can be distinguished from fatalism and predestination because it relies on natural law. Isaac Kramnick points out the paradox of Priestley's positions: as a reformer, he argued that political change was essential to human happiness and urged his readers to participate, but he also claimed in works such as Philosophical Necessity that humans have no free will. Philosophical Necessity influenced the 19th-century utilitarians John Stuart Mill and Herbert Spencer, who were drawn to its determinism. Immanuel Kant, entranced by Priestley's determinism but repelled by his reliance on observed reality, created a transcendental version of determinism that he claimed allowed liberty to the mind and soul.

In the last of his important books on metaphysics, Letters to a Philosophical Unbeliever (1780), Priestley continues to defend his thesis that materialism and determinism can be reconciled with a belief in a God. The seed for this book had been sown during his trip to Paris with Shelburne. Priestley recalled in his Memoirs:

As I chose on all occasions to appear as a Christian, I was told by some of them, that I was the only person they had ever met with, of whose understanding they had any opinion, who professed to believe Christianity. But on interrogating them on the subject, I soon found that they had given no proper attention to it, and did not really know what Christianity was ... Having conversed so much with unbelievers at home and abroad, I thought I should be able to combat their prejudices with some advantage, and with this view I wrote ... the first part of my ‘Letters to a Philosophical Unbeliever’, in proof of the doctrines of a God and a providence, and ... a second part, in defence of the evidences of Christianity.

The text addresses those whose faith is shaped by books and fashion; Priestley draws an analogy between the skepticism of educated men and the credulity of the masses. He again argues for the existence of God using what Schofield calls "the classic argument from design ... leading from the necessary existence of a creator-designer to his self-comprehension, eternal existence, infinite power, omnipresence, and boundless benevolence." In the three volumes, Priestley discusses, among many other works, Baron d'Holbach's Systeme de la Nature, often called the "bible of atheism." He claimed that d'Holbach's "energy of nature," though it lacked intelligence or purpose, was really a description of God. Priestley believed that David Hume's style in the Dialogues Concerning Natural Religion (1779) was just as dangerous as its ideas; he feared the open-endedness of the Humean dialogue.