Joseph Priestley as an heir of Newton

ABSTRACT

Like most Enlightenment philosophers, Priestley acknowledges his debt to Newton. However, despite his mentor’s prohibition against “making hypotheses”, in the 1770s, he embarked on a surprising metaphysical epic that led him, the theologian and scientist, to develop in his Disquisitions a bold system that articulated materialism, necessity and Socinianism. This synthesis constitutes the originality of a thinker who wanted to reapprehend science, metaphysics and theology together at the very moment when their dispersion seemed inevitable (and to give them an educational and political extension). It is based on a monistic ontology to which Priestley did not hesitate to give the unexpected name of materialism, at the risk of a number of misunderstandings, while he claims, much to the dismay of Reid, to closely follow the method of Newton. This paper will focus on the relation between Priestley and Newton’s ambiguous inheritance. What is Priestley’s “science” made of? What is its relationship to Newton and his “rules”, to mathematics, to the theory of language, to the so-called “analysis and synthesis method”, to Boscovich? How important is his claim for hypotheses and metaphysics? If Priestley indeed was a Newtonian, he surely was an unorthodox one.     

Priestley on materialism and the essence of God

ABSTRACT

The paper focuses on Priestley’s complex views on the essence of God in connection with his materialism, elaborated in the Disquisitions Relating to Matter and Spirit (1777/ 1782). This issue is crucial if one wishes to get a clear idea of what Priestley’s materialism amounts to; whether it is mainly a thesis about the material grounds of the human mind (“psychological materialism”), or a more far-reaching one about what kind of substances exist in the world (a version of “ontological materialism”). The claim that God may be material allows for the most radical version of ontological materialism according to which everything in the world is material, without altogether denying that God exists. In fact, Priestley considers and partially defends at least three different views on the potential materiality of God: (1) an agnostic stance that is his official view, (2) materialism about God based on his own theory of matter, and (3) “gross” materialism about God. The aim of the paper is to analyze these three views, in particular concerning what kind of materialism they support and whether they can contribute to the consistent Christian materialism Priestley envisaged.     

From the logic of ideas to active-matter materialism: Priestley’s Lockean problem and early neurophilosophy

ABSTRACT

Empiricism is a claim about the contents of the mind: its classic slogan is nihil est in intellectu quod non fuerit in sensu, “there is nothing in the mind (intellect, understanding) which is not first in the senses.” As such, it is not a claim about the fundamental nature of the world as material. I focus here on in an instance of what one might term the materialist appropriation of empiricism. One major component in the transition from a purely epistemological claim about the mind and its contents to an ontological claim about the nature of the world is the new focus on brain–mind relations in the eighteenth century. Here I examine a Lockean trajectory as exemplified in Joseph Priestley’s 1777 Disquisitions Relating to Matter and Spirit. However, Locke explicitly ruled out that his inquiry into the logic of ideas amounted to a “physical consideration of the mind.” What does it mean, then, for Priestley to present himself as continuing a Lockean tradition, while presenting mental processes as tightly identified with “an organical structure such as that of the brain” (although he was not making a strict identity claim as we might understand it, post-Smart and Armstrong)? One issue here is that of Priestley’s source of “empirical data” regarding the correlation and indeed identification of mental and cerebral processes. David Hartley’s theory in his 1749 Observations on Man was, as is well known, republished in abridged form by Priestley, but he discards Hartley’s “vibratory neurophysiology” while retaining the associationist framework, although not because he disagreed with the former. Yet Hartley was, at the very least, strongly agnostic about metaphysical issues (and it is difficult to study these authors while bracketing off religious considerations). One could see Locke and Hartley as articulating programs for the study of the mind which were more or less naturalistic (more strongly so in Hartley’s case) while avoiding “materialism” per se; in contrast, Priestley bit the (materialist) bullet. In this paper I examine Priestley’s appropriation and reconstruction of this “micro-tradition,” while emphasizing its problems.     

Priestley and Kant on materialism

ABSTRACT

Kant maintains in the Critique of Pure Reason that both materialism and spiritualism cannot explain our existence. This paper argues that Kant’s relation to (psychological) materialism is more complex than this rejection suggests and is usually thought, and it evaluates this relation in a new and more positive light. The paper shows that Priestley anticipates some of Kant’s arguments against rationalist psychology, and that Kant’s rejection of materialism does not commit him to an immaterialist metaphysics of the soul. These arguments involve a discussion of the problem of the unity of consciousness and of notions such as simplicity and identity.     

Priestley in Germany

ABSTRACT

The paper focuses on the reception of Priestley in Germany, which is remarkable for the huge and assiduous interest it raised in different philosophical milieus. Priestley’s dynamical conception of matter, his explanation of the functioning of the brain, and of the production of material ideas are at the basis of the new form of materialism that develops in Germany in the late 1770s, and which differs completely from the model of mechanical materialism Germany was used to in earlier decades. Indeed, the German reception of Priestley’s ideas begins surprisingly early, just one year after the publication of his edition of Hartley’s Observations on Man (1775), and traverses the two final decades of the eighteenth century with a considerable number of reviews and references in the main philosophical journals and works of the time. In 1778, his introduction to the Observations was translated into German and presented in the form of a manifesto of a new materialistic philosophy compatible with the claims of morals and religion. Within a few years, Priestley became the unavoidable reference point for the most relevant theological and philosophical discussions concerning the nature of matter and spirits, the place of God, the possibility of human freedom, and the legitimacy of free thinking.