The English works of Thomas Hobbes of Malmesbury, Volume 07 (of 11)

In Short

This seventh volume of collected English works presents a specialized look at the philosopher’s late-career pivot toward natural science and mathematics. It gathers seven distinct inquiries into physical phenomena—ranging from gravity and tides to the mechanics of light and heat—alongside a series of heated exchanges with contemporary academics. By insisting that all observable reality can be explained through the movement of bodies, the text provides a fascinating window into the seventeenth-century struggle to codify the laws of nature. Its enduring power lies in its unflinching, argumentative spirit and its attempt to bridge abstract geometry with tangible, physical reality.

The Story

The progression of this work moves from the observational to the intensely polemical. It opens with a dedication to the King, establishing the author’s intent: to apply the principles of motion to the natural world. Through a structured dialogue, the text systematically deconstructs everyday phenomena. The interlocutors debate why a window appears to move when one is intoxicated, how a spark of fire can seem to be a line of light, and why the sea ebbs and flows. The central argument is consistent throughout: all effects are essentially "pression" or motion. A beam of light, for example, is not a mysterious substance but an action, a series of pressures passing through a medium.

As the text transitions from these "Philosophical Problems" into the realm of geometry, the tone sharpens significantly. The author shifts from a teacher explaining the mechanics of the universe to a defender of his own mathematical reputation. He directly addresses the Savilian professors of mathematics at Oxford, setting out his definitions of quantity and dimension. He rejects the current application of arithmetic to geometry, arguing that modern mathematicians have abandoned the clarity of classical logic for a "symbolic tongue" that obscures rather than reveals truth.

The arc concludes with a series of aggressive, detailed rebuttals against Dr. John Wallis. The author is no longer merely defining terms; he is engaged in a war of logic. He meticulously dissects his opponent’s errors regarding infinite series, angles of contact, and the nature of a point. He treats these mathematical disagreements not as academic oversights, but as fundamental failures of reason. The final pages are less a scientific treatise and more a battlefield, where he defends his personal conduct, dismisses claims of arrogance, and insists that his controversial methods are the only ones capable of producing rigorous proof. Throughout the volume, the movement is from the broad, curious investigation of how the world works to an intense, narrow focus on how the world must be thought about, ending on a note of defiant intellectual isolation.

How It Unfolds

The mechanics of sense The book begins by defining the relationship between body and mind, asserting that our senses are mere "fancy" triggered by external motion. The dialogue between the two participants establishes the foundational rule that all action is simply change of place.

The natural world explained The author applies this framework to various physical puzzles, such as the behavior of tides, the nature of heat, and the properties of hard versus soft bodies. By reducing complex events to the movement of particles, he attempts to strip away the mystery of natural phenomena.

The geometric challenge The focus shifts to formal geometry, where the author critiques standard practices of measurement. He argues for a more precise, foundational approach to defining quantity, challenging the established experts to rethink their basic axioms.

The war of words The latter half of the book descends into a series of sharp, increasingly personal letters and papers. The author systematically attacks the credibility of his mathematical rivals, particularly Dr. Wallis, accusing them of logical absurdity and deliberate obfuscation.

The final defense The work culminates in a detailed refutation of specific mathematical claims, blending technical critique with social commentary. The author concludes by justifying his own combative tone, framing his refusal to yield as a necessary defense of truth against academic incompetence.

The People

The text is driven primarily by the author, who presents himself as a clear-eyed champion of "natural causes." He is deeply suspicious of ambiguity and holds a profound, often stinging, contempt for those who use "equivocation" or confusing symbols to disguise flawed logic. He is a man who values the definition above the consensus, willing to alienate every peer in his field to maintain the integrity of his internal system.

Opposing him is Dr. John Wallis, the primary target of his ire. Within these pages, Wallis is not merely a mathematician but a symbol of the "absurd." The author portrays him as someone who hides behind complex symbols and obscure language to mask the fact that he does not understand the fundamental principles of geometry. He is the foil against which the author hones his own reputation for precision.

The two interlocutors in the early dialogues act as a surrogate for the reader. One is the seeker, asking probing, often naïve questions about flame or gravity, while the other—representing the author’s voice—patiently but strictly guides the inquiry toward the correct mechanical explanations. They undergo no character arc; their role is to serve the logic of the argument, ensuring that the reader understands the necessity of "niceness" in defining the terms of the universe.

In Its Own Voice

The doctrine of natural causes hath not infallible and evident principles. For there is no effect which the power of God cannot produce by many several ways.

This preface acknowledges the limitations of human knowledge when attempting to explain the physical world.

The smallest spark of fire flying up seems a line drawn upward; and again by that swift circular motion which we have supposed for the cause of light, seems also broader than it is.

This observation on the nature of light illustrates the author’s method of explaining sensory perception through physical motion.

It is well, and I take it to be an honour to be the first that do so.

The author defends his controversial definition of a "point" as a body whose magnitude is not considered in a demonstration.

What It's Really About

At its core, this book is an argument for the absolute necessity of rigorous definitions in human thought. It is not just about tides or geometry; it is about the "equivocation" that the author believes rots philosophy from within. He is deeply concerned that the lack of shared, precise language—and the reliance on metaphors or symbols—has led to a state of permanent discord among scholars. He asks whether we can ever truly know the cause of an event if we cannot agree on the basic, mechanical definition of the objects involved. The text is a plea for a world where "fancy" is separated from fact, and where logic is the only currency of value.

Why Read It Today

Readers who enjoy the history of ideas will find this book deeply rewarding, though it is not an easy read. The prose is dense, seventeenth-century English, and the author’s relentless, vitriolic focus on mathematical pedantry can be exhausting. It feels less like a modern textbook and more like sitting in a room with a brilliant, argumentative, and deeply frustrated man who is determined to have the last word.

You will appreciate the book if you are interested in the transition from medieval natural philosophy to the mechanical worldview of the Enlightenment. It offers a rare, unfiltered look at the ego and the intellect of a man who, while often wrong by modern standards, was consistently obsessed with finding the "natural causes" of things. The experience of reading it is like witnessing a high-stakes intellectual brawl; it is marked by flashes of brilliant, simple insight into the physical world, followed by long, tedious stretches of defensive maneuvering. If you can push through the technical jargon and the personal feuds, you are left with the portrait of a mind that treats every disagreement as a moral failing. What stays with you is the author's unwavering conviction that truth is not something to be negotiated, but something that must be defined with such clarity that it becomes impossible to misinterpret.