Common sense

Lore & Background

The term 'common sense' originates in the works of Aristotle, where it referred to a faculty within the animal soul that perceives real things based on different sensory perceptions from distinct senses. This original meaning, often called Sensus communis in medieval Latin, was developed by philosophers of the medieval Latin and Arabic tradition, including Al-Farabi, Avicenna, Averroës, Albert, and Thomas, who found in Aristotle's De Anima and Parva Naturalia the elements of a coherent doctrine of a central faculty of the sensuous soul. A second philosophical use, Roman-influenced, emerged during the Roman Empire, referring to a natural human sensitivity for other humans and the community, possibly influenced by Stoic Greek terms such as koinḗ énnoia (shared notions) and koinonoēmosúnē (public spirit).

Reader's Guide

The concept of common sense acquired its modern English meaning at the beginning of the 18th century: 'Those plain, self-evident truths or conventional wisdom that one needed no sophistication to grasp and no proof to accept.' This development was partly a reaction to Descartes's critical remarks about the French term bon sens in his Discourse on Method, where he stated that everyone has a similar amount of common sense but it is rarely used well, advocating instead for a skeptical logical method. During the Enlightenment, common sense came to be seen more positively as the basis for empiricist thinking, contrasted with metaphysics associated with the Ancien Régime. Today, the concept remains linked to perennial topics in epistemology and ethics, with special focus on the philosophy of the modern social sciences.

Did You Know?

• The original historical meaning of common sense, from Aristotle, refers to a faculty that perceives real things based on different sensory perceptions from distinct senses.
• The Roman meaning of sensus communis emphasized a natural human sensitivity for other humans and the community, possibly influenced by Stoic philosophy.
• Descartes argued in Discourse on Method that everyone has a sufficient amount of common sense but it is rarely used well, so a skeptical method should be followed.

Ancient Roots and Stoic Influences

The concept of common sense traces back to Aristotle's De Anima and Parva Naturalia, where he proposed a central faculty within the animal soul (psūkhḗ) that perceives real things by integrating inputs from distinct senses—sights, sounds, smells. This Aristotelian notion proved remarkably resilient, shaping medieval Latin and Arabic philosophical traditions from Al-Farabi through Avicenna, Averroës, Albert, and Thomas Aquinas, who all drew scattered elements from those texts to build a coherent doctrine of the sensuous soul's central faculty. Beyond Aristotle, Roman-era Stoic philosophers introduced parallel concepts using the Greek word koinḗ (meaning common or shared): koinós noûs (common mind or reason), koinḗ énnoia (shared notions or common conceptions in-born or imprinted by the senses), and koinonoēmosúnē, a term appearing only in Marcus Aurelius's Meditations. C.S. Lewis noted that koinós noûs, as used by Epictetus, closely resembles the modern English idea of common sense as the elementary mental outfit of the normal man. These layered ancient meanings—sensory integration, shared rational capacity, communal awareness—form the deep substrate from which the modern English term eventually emerged.

The Enlightenment Revaluation

In the early 18th century, the old philosophical term sensus communis underwent a transformation that gave it its modern English sense: plain, self-evident truths requiring no sophistication to grasp or proof to accept, precisely because they aligned with the basic intellectual capacities of the whole social body. This shift was partly a reaction to René Descartes, who in the opening line of Discourse on Method declared that everyone possesses a similar and sufficient amount of bon sens, yet rarely uses it well, arguing instead that a skeptical logical method must be followed and common sense should not be overly relied upon. The ensuing Enlightenment era reversed this skepticism, recasting common sense positively as the foundation for empiricist modern thinking. It became contrasted with metaphysics and Cartesianism, both associated with the Ancien Régime. The term thus became entangled in the great dispute between rationalism and empiricism and in arguments over scientific method, serving as both a standard for good taste and logical axioms and, conversely, a label for conventional wisdom, vulgar prejudice, and superstition.

Political Firepower and Rhetorical Ambiguity

The concept of common sense has wielded extraordinary political force. Thomas Paine's 1776 pamphlet Common Sense has been described as the most influential political pamphlet of the 18th century, shaping both the American and French revolutions by invoking the idea that certain truths are so plain they need no elaborate justification. In philosophical and scientific discourse since the Enlightenment, the term has been deployed rhetorically with deliberate ambiguity: approvingly, it signals good taste, sound judgment, and the source of scientific and logical axioms; disapprovingly, it dismisses ideas as mere conventional wisdom, vulgar prejudice, or superstition. This dual valence makes it a powerful rhetorical tool in debates spanning science, politics, and economics. The English term, in particular, developed these layered shades of meaning more distinctly than other Western European languages—French bon sens, for instance, does not map neatly onto every English usage—and the English formulation has since become the international standard. The interplay between its approving and dismissive registers continues to shape how arguments about knowledge, ethics, and social organization are framed.

Interconnected Meanings and Enduring Relevance

The various meanings of common sense are not isolated definitions but form a complex, interwoven history. The Aristotelian sensory faculty, the Roman-influenced sense of natural human sensitivity toward others and community, and the everyday notion of basic practical judgment all refer to a type of fundamental awareness and ability to judge that most people are expected to share naturally, even when they cannot articulate why. These meanings evolved through major political and philosophical debates in modern Western civilization, particularly concerning science, politics, and economics. The interplay between them is especially pronounced in English, where the term has accumulated more distinct shades than its counterparts in other Western European languages, and the English formulation has in turn become the international reference point. Today, the concept and the question of how it should best be employed remain central to perennial topics in epistemology and ethics, with particular focus on the philosophy of the modern social sciences. The term's resistance to a single fixed definition is itself a testament to its depth and its ongoing relevance in how societies reason about what is self-evident and what requires argument.

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