Articles

Picture a universe made up of an infinity of points of view, each of them a minuscule soul that, without ever looking out of a window, mirrors the entire cosmos within itself — and which is nonetheless in perfect agreement with all the others, as though every clock in a vast hall had been set once and for all to strike the same hour for eternity. This is the world of Gottfried Wilhelm Leibniz (1646–1716): the last great universal scholar of the modern age — mathematician, logician, jurist, diplomat, historian and theologian — who attempted the most ambitious of syntheses, reconciling the mechanical science of his time with a metaphysics of substances and with Christian theology. His philosophy is at once one of the most coherent systems ever built and one of the bridges that connect Aristotle to the mathematical logic of the twentieth century. ...

Imagine that all of Western philosophy, from Parmenides to Heidegger, had committed the same fundamental gesture: reducing what is different to what is identical, absorbing the strange into the familiar, converting the Other into an object of my knowledge. This is the charge that runs through the work of Emmanuel Lévinas (1906–1995). Against a tradition that made the question of being its supreme concern, Lévinas asserts something apparently simple and radically subversive: prior to ontology there is ethics. Before I understand the world, I am already bound by a face that looks at me and says “thou shalt not kill.” ...

For decades, philosophy textbooks treated Simone de Beauvoir as an appendix to Jean-Paul Sartre — the gifted companion who applied to the “woman question” ideas that were supposedly not her own. That reading is tenacious, but recent scholarship contests it: Beauvoir was an original philosopher whose contributions to existentialist ethics and to the theory of oppression anticipate, on decisive points, formulations later credited to Sartre. And it was she, not he, who produced the work that would give twentieth-century feminism its philosophical foundation. To read Beauvoir as a thinker in her own right is not a gesture of historiographical courtesy: it is a demand of rigor. ...

Few philosophers have written two works so different that one seems to refute the other — and yet have seen both become classics. Ludwig Wittgenstein is the paradigm case. The young man who in 1921 published the Tractatus Logico-Philosophicus, convinced he had definitively solved the problems of philosophy, is the same man who, three decades later, left in the Philosophical Investigations a meticulous critique of his own early theses. Between the two works lies not only a theoretical turn but one of the most singular intellectual stories of the twentieth century. To understand Wittgenstein is to understand two opposed ways of thinking about what language is and what philosophy can do. ...

A Silent Moral Revolution In 1975, Australian philosopher Peter Singer published Animal Liberation — a book that would become one of the philosophically most practically impactful texts of the twentieth century, giving decisive impetus to the animal rights movement and motivating legislative changes in several countries. The central thesis is at once simple and radical: the exclusion of non-human animals from full moral consideration has no rational justification — it is a form of prejudice comparable to racism and sexism. ...

The Birth of a Field The term bioethics was coined by oncologist and biochemist Van Rensselaer Potter in 1971, in his book Bioethics: Bridge to the Future. For Potter, bioethics was a synthetic discipline bridging the biological sciences and human values — a “bridge” capable of guiding humanity in the face of risks that technological progress posed to the survival of the species and the ecosystem. Potter conceived bioethics broadly, in an almost environmental sense, encompassing the relationship between human beings and the entire biosphere. ...

Democracy as a Philosophical Problem Democracy is not merely a political regime — it is a first-order philosophical problem. It raises questions about the nature of legitimacy (why do collective decisions bind those who disagree?), about the relationship between facticity and normative validity (how can positively enacted norms aspire to rational validity?), and about the very possibility of a public space of shared reasons in societies marked by deep value pluralism. Deliberative democratic theory is the twentieth century’s most systematic attempt to answer these questions from a philosophical standpoint rooted in the Enlightenment tradition. ...

The Problem of Ethics in the Technological Age Philosophical ethics, from the Greeks to Kant, was elaborated for a world of limited human reach. Human actions affected the immediate surroundings — the polis, the family, one’s contemporaries. The distant future and non-human nature remained outside the scope of moral consideration: they were domains of theology, cosmology, or simply immutable givens of the setting in which ethics operated. The technological development of the twentieth century radically altered this picture. The human capacity for action — to transform, destroy, and create — acquired planetary scale and a temporal reach extending across generations. The atomic bomb, genetic engineering, global ecological degradation: these realities pose ethical problems that available traditions were simply never designed to address. ...

Technology and Ethics: An Old Relationship, A New Problem Ethical concern about technological power is not new. In the twentieth century, Norbert Wiener — MIT mathematician and founder of cybernetics — devoted the book The Human Use of Human Beings (1950) to reflecting on the moral and social implications of automated machines. Wiener warned of the risks of systems that, once in operation, produce consequences independent of their creators’ original intentions, and of the possibility that automation would generate mass unemployment and concentration of power. ...

Introduction: The Fundamental Question “What is law?” This apparently simple question has divided thinkers for millennia. It is not merely a technical matter for lawyers: it is a profound philosophical question about the relationship between statute and morality, power and justice, what law is and what it ought to be. The answers given to it have structured entire traditions and determined how courts decide cases that affect real lives. Two great currents dominate Western legal philosophy: natural law theory (or jusnaturalism), which affirms a necessary connection between positive law and superior moral or rational principles; and legal positivism, which insists on a conceptual separation between the law as it is and the law as it ought to be. The debate between these currents — deepened, transformed, and partly transcended in the twentieth century by Hart, Fuller, Dworkin, and Alexy — remains at the centre of contemporary legal-philosophical reflection. ...

Philosophy of religion is one of the most expansive and contested fields in philosophy. Its subject matter is not religion as a social or cultural phenomenon — that falls to sociology and anthropology — but the truth claims that religious traditions make: that God exists, that the world was created, that there is life after death, that certain texts are revealed. The philosophical question is not “why do people believe?” but “are there reasons to believe?” and “what does belief mean?” ...

Pragmatism is America’s most original contribution to the history of philosophy. Born in the late nineteenth century in the wake of the Civil War, amid scientific expansion and industrial transformation, pragmatism refused both European rationalism and British empiricism to propose an alternative: philosophy should be judged by what it does, not by what it contemplates; ideas are instruments of action, not mirrors of reality. This article traces classical pragmatism — Peirce, James, Dewey, Mead — and the neopragmatism of the twentieth century — Rorty, Putnam, Brandom, Misak. ...

In 1963, Edmund L. Gettier (1927–2021) published in the journal Analysis a three-page article titled “Is Justified True Belief Knowledge?” (Analysis 23, 1963, pp. 121–123). In fewer than a thousand words, Gettier overturned a consensus of more than two millennia: the definition of knowledge as justified true belief. Rarely has so short a paper produced so lasting an impact in the history of philosophy. 1. The Classical Definition: JTB The tripartite definition of knowledge — knowledge as Justified True Belief (JTB) — is often traced to Plato’s dialogue Theaetetus (c. 369 BC), where Socrates successively examines and refutes three definitions of knowledge. In the passage known as the “account” definition (logon didonai, 201d–210a), something close to the JTB conception appears, though Plato ultimately rejects it as well. ...

The Problem and Its Persistence Few philosophical problems are simultaneously so ancient and so resistant as the mind-body problem. In its simplest formulation: what is the relationship between the mind — with its thoughts, sensations, emotions, experiences — and the body, especially the brain? The question seems immediate and even obvious; the difficulty lies in answering it without falling into contradictions or into mysteries greater than the original. Two types of answer present themselves. Dualism holds that mind and body are of distinct natures — that there is something in the mind that cannot be reduced to the physical. Monism holds that there is only one kind of substance or property: in its materialist (or physicalist) version, everything is ultimately physical. The history of philosophy of mind is largely the history of the tension between these positions and of the attempts to overcome it. ...

Twentieth-century philosophical aesthetics has no single center. It bifurcates into at least two major traditions — continental and analytic — each with its own problematics, yet converging by different paths on a common question: what is art? And, inseparably: what happens to art when technical reproduction dissolves the singularity of the work, when the market turns culture into commodity, when a signed urinal is exhibited in a museum? This article traces the fundamental lines of twentieth-century aesthetics, from the founding texts of Benjamin and Adorno to the analytic theories of Danto and Goodman. ...

The Problem Suppose every thought you have, every decision you make, every movement of your body is the necessary result of prior brain states — which in turn result from prior physical states, in a chain stretching back to the Big Bang. If that is true, in what sense are you free to do otherwise than you do? And if you are not free, how can you be held morally responsible for your actions? ...

The Puzzle What makes you the same person you were at age five? The cells in your body have almost completely renewed. Your beliefs, desires, and memories are radically different. Physically and psychologically — nearly everything has changed. And yet we say it is the same person. Why? And if you suffered complete amnesia tomorrow — with no memory of today — would it still be “you”? And if your brain were divided and each half transplanted into a different body, which of the two would be you? ...

What Is Phenomenology? “Back to the things themselves!” — this methodological principle, associated with Edmund Husserl, summarizes the fundamental motivation of phenomenology: to abandon abstract theoretical constructs, unverified metaphysical hypotheses, and the presuppositions of scientific naturalism, in order to return to a rigorous description of experience as it presents itself to consciousness. The name “phenomenology” literally means the study (logos) of phenomena (phainomena) — of what appears, what manifests. But what appears is not something behind which the “thing-in-itself” lurks hidden: the phenomenon, for Husserl, is precisely what gives itself to consciousness in its appearing, and it is this appearing that phenomenology investigates. ...

Language as a Philosophical Problem Why did language become the central philosophical concern of the twentieth century? Several reasons converge. First, the discovery that many classical philosophical problems resulted from linguistic confusions — misunderstandings about the logical form of propositions. Second, the recognition that understanding how language works is understanding how we think and how we relate to the world. Third, the logical revolution initiated by Frege, which provided rigorous tools for linguistic analysis. ...

The Encounter That Defined an Era In 1971, John Rawls (1921–2002) published A Theory of Justice — a work that revived normative political philosophy after decades of positivist dominance. Three years later, in 1974, Robert Nozick (1938–2002) responded with Anarchy, State, and Utopia, which became the most rigorous libertarian critique of the Rawlsian program. Both were professors at Harvard. The debate they conducted — personally amicable, philosophically radical — remains the most productive confrontation in twentieth-century Anglo-American political philosophy. ...