Stanford philosopher strengthens Kant’s connection to natural science and Newton

Research by philosophy Professor Michael Friedman reveals how a lesser-known Kantian text serves as an important bridge between Kant’s concepts of metaphysics and natural science, as well as between defining periods in Kant’s development.


German philosopher Immanuel Kant’s "Metaphysical Foundations of Natural Science" is the subject of Stanford Professor Michael Friedman’s newest book.

In the 18th century, German philosopher Immanuel Kant penned works that defined the boundaries and frontiers of human reason.

Through a meticulously close reading of Kant’s work, Stanford philosopher Michael Friedman ’s latest research demonstrates that many scholars have previously underplayed or misunderstood the impact of Isaac Newton’s scientific writings on the eminent philosopher’s thought.

Friedman’s discoveries explain how Kant’s work was, in fact, "profoundly influenced by Newtonian mathematical physics." The study also gives fresh importance to the Metaphysical Foundations of Natural Science (1786), a Kantian text that often takes a back seat to the philosopher’s better-known works

In his latest book, Kant’s Construction of Nature , published by Cambridge University Press, Friedman reveals a fuller range of philosophical and scientific implications from Kant’s "extremely compressed" text.

A scholar of both the philosophy of science and the history of philosophy, Friedman makes an extensive case for the relevance of Kant’s deep connection to the natural and exact sciences, especially Newtonian science. "Nowhere in Kant’s oeuvre is the link more pivotal," says Friedman, "than in the Foundations."

Unlike previous studies of the bridge between the Foundations and Newton, Friedman says his text is structured as "a reading of Kant’s text … distinct from both a fully contextualized intellectual history and from a more traditional line-by-line commentary."

Friedman argues that "a better understanding of the way in which Kant, in this work, fashioned a fruitful synthesis of Newtonian physics and Leibnizean metaphysics can also further a better understanding of the deep conceptual transformation that began with Kant and concluded with the revolutionary new (Einsteinian) space-time theories."

Newton, Friedman asserts, provided "the best example of rational and objective knowledge of the natural world" of Kant’s time. In Friedman’s view, Kant’s writings draw support, if not always obviously, from Newton’s theories of gravity, motion, and more.

Text as evidence

Rather than tracing the origins of the philosophical discoveries and debates that could have influenced Kant to write the Foundations as he did, Friedman reconstructed Kant’s main message by relying on the text itself as evidence.

Friedman says that he thereby "aimed to elucidate the meaning of this difficult text by a process of ’triangulation’ that locates it within the wider intellectual context of the Leibnizean metaphysical tradition, Kant’s own metaphysical writings, and Newton’s writings in physics and natural philosophy."

Kant organized the Foundations in four parts: phoronomy (now referred to as kinematics, a branch of classical mechanics), dynamics, mechanics and phenomenology.

Similarly, Friedman wrote a chapter corresponding to each of those parts, closely reading the text, reconstructing Kant’s meaning, and then showing how he must have used Newton’s laws of motion as frames of reference to develop original physico-mathematical principles.

As one example, Friedman lays out an argument that Kant viewed Newton’s theory of universal gravitation as "the only proper natural science" for which Kant hoped to provide a metaphysical foundation. In this context, Kant needed a framework that would let him conceptually reduce all motion and rest to absolute space. Absolute space defines a privileged, immovable frame of reference for the moving bodies (such as planets) that occupy it.

According to Friedman, Kant reconstructed Newton’s universal gravitation as a "genuine action at a distance through empty space" so that he could "generate a determinate distinction between true and merely apparent motion."

Motion of matter

This uniquely Newtonian idea was vital to Kant, Friedman says, because it alone enabled him to conceive of the motion of matter as a genuine object of experience – a thing capable of being known.

Further, said Friedman, "Kant aimed to provide a deeper philosophical understanding of Newton’s work by providing it with a metaphysical foundation using a radically transformed version of Leibnizean metaphysics."

On this basis, Friedman affirms that Kant’s Metaphysical Foundations is not a distraction, but rather a central work that can help people make sense of Kant’s more famous texts, including pivotal revisions between the first (1781) and second (1787) editions of The Critique of Pure Reason.

Friedman, who further developed his ideas while a fellow at the Stanford Humanities Center last year, hopes his findings will lead to more work on the study of what was, at the end of the 18th century, a watershed moment for how philosophers and physicists conceived of science itself.