The sciences and humanities are often imagined as two entirely distinct fields with little overlap. In this book, Gordon Gillespie weaves together historical anecdotes, philosophical arguments, and scientific explanations to demonstrate how mathematics is the bridge that connects them. Gillespie constructs this case through a careful selection of thought-provoking vignettes that illustrate foundational topics, such as counting and geometry, as well as the philosophical ideas behind concepts like infinity. As the chapters progress, Gillespie gradually deconstructs the historical understanding of mathematics as a purely abstract discipline. In its place, readers will instead see it for what it really is: not the drudgery of uncreative number crunchers, but a unique art of thinking that builds intricate ideas from elementary notions deeply rooted in our everyday lives. Whether these ideas come from Special Relativity or the well-known story about Achilles and the tortoise, The Oracle of Numbers shows how mathematics operates across disciplines and opens up unique perspectives on the world and ourselves.

Reviews of the German edition:

"Gordon Gillespie captivates the reader with a very unique approach. [...] What is impressive about Gillespie's book, apart from the wealth of examples, is his talent for clearly explaining abstract relationships. [...] Here one learns that exact standards of reasoning and creative thinking are not mutually exclusive." André Behr, Neue Zürcher Zeitung am Sonntag

"In his popular non-fiction book, the author succeeds in presenting key mathematical concepts in a way that can be understood even by those with no background in mathematics. [...] This volume motivates teachers of mathematics and philosophy to address central questions of the philosophy of mathematics in a problem-oriented manner in their subject lessons or in interdisciplinary projects. [...] Conclusion: Gordon Gillespie's 'The Oracle of Numbers' is a very good and entertaining introduction to the philosophy of mathematics." Marcel Remme, Zeitschrift für Didaktik der Philosophie und Ethik

"The author has written a highly demanding work. [The reader] must be prepared to think deeply [...] but it is worth it: the confrontation leads [...] to a productive questioning and enrichment of one's own perspective and way of thinking." Hartmut Weber, Spektrum der Wissenschaft

Gordon Gillespie is an actuary, quantitative risk manager and data scientist. He has a doctorate in philosophy. In 2025, an essay based on this book has been published in Aeon Magazine under the title “Beyond Causality”. Therein he summarizes and further develops a train of thought from the book about causal vs. structural forms of explanation. Gordon Gillespie lives in Rüdesheim, Germany.