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.