Scottish Common Sense Realism

Historical Background and Development

Scottish Common Sense Realism is an influential school of philosophy that arose in 18th-century Scotland, chiefly as a reaction to the skepticism and idealism associated with thinkers such as David Hume and George Berkeley. Its founding figure is Thomas Reid (1710–1796), professor at Aberdeen and later at Glasgow, whose major works include An Inquiry into the Human Mind on the Principles of Common Sense (1764) and Essays on the Intellectual Powers of Man (1785).

Reid and his followers believed that much of early modern philosophy, beginning with René Descartes and continued by Locke, Berkeley, and Hume, had taken a wrong turn. By treating ideas in the mind as intermediaries between the mind and the world, these philosophers seemed to open the door to doubts about whether an external world exists at all, whether other minds are real, and whether we can have knowledge of cause and effect. Scottish Common Sense Realists sought to close this skeptical gap by returning to what they called principles of common sense: basic beliefs held by all normal human beings in ordinary life.

The movement developed at the universities of Aberdeen, Glasgow, and Edinburgh, and it became a defining feature of the Scottish Enlightenment. Important figures after Reid include Dugald Stewart, who popularized Reid’s ideas and systematized them for teaching, and James Beattie, who wrote widely read polemics against Humean skepticism.

By the early 19th century, Scottish Common Sense Realism had spread beyond Scotland. It became highly influential in America, especially in the early philosophy of Princeton and other colleges, and it played a role in shaping New England theology and aspects of American religious and moral thought. While it declined in influence in late 19th- and early 20th-century academic philosophy, many of its themes later resurfaced in analytic philosophy and in so-called reformed epistemology.

Core Doctrines and Method

At the heart of Scottish Common Sense Realism is the claim that philosophy must start from, and respect, the ordinary beliefs of common sense. These include beliefs such as:

• There is a material world existing independently of our minds.
• We have bodies and other people have minds like our own.
• Our senses generally give us reliable information.
• Memory and testimony (the word of others) are normally trustworthy.
• There are basic moral distinctions between right and wrong.

Reid called these first principles or principles of common sense. According to him, they are self-evident, meaning they do not need further proof and cannot be overturned by theoretical argument without undermining the practice of reasoning itself. Proponents argued that even skeptics rely on these principles in everyday life—when walking around obstacles, speaking to others, or trusting their own memories—so denying them in theory is inconsistent.

A second core doctrine is direct realism about perception. Instead of saying that we immediately perceive only internal ideas or sense-data, Scottish Common Sense Realists held that we directly perceive external objects and their qualities. When a person sees a tree, what is immediately known is not an internal representation but the tree itself. While they acknowledged that perception involves complex mental processes, they insisted that the immediate object of perception is the external thing, not a mental copy.

Their method was largely empirical and descriptive, but grounded in everyday experience rather than in laboratory experiments. Reid carefully observed how language works, how children learn, and how people normally behave, hoping to uncover the basic principles that underlie human cognitive and moral life. This approach was sometimes described as a “philosophy of human nature.”

On ethics, Scottish Common Sense Realists maintained that moral knowledge is also rooted in common sense. Ordinary people, they argued, recognize that gratitude, justice, benevolence, and honesty have intrinsic moral value. Conscience and moral sentiments are treated as reliable guides, not infallible, but fundamentally trustworthy in the absence of special reasons for doubt. Moral duties, on this view, are as evident to normal human understanding as the existence of the external world.

In epistemology more broadly, the school advanced an early form of what is now called reliabilism or externalism: our basic cognitive faculties (sensation, memory, reasoning, testimony) are presumed reliable unless we discover specific reasons to mistrust them. We are justified in accepting their deliverances because human life, communication, and science all presuppose that they are generally trustworthy.

Influence, Legacy, and Criticisms

Scottish Common Sense Realism exercised substantial influence in the Anglophone world. In Scotland and England, it shaped university curricula, especially through the textbooks and lectures of Dugald Stewart and his successors. In the United States, it became the dominant philosophical outlook in many colleges from the late 18th to the mid-19th century, helping to mold Protestant theology, moral philosophy, and early American psychology.

Later philosophers took up some of its themes in new ways. In the 20th century, aspects of the movement influenced ordinary language philosophy and certain strands of analytic epistemology that resisted radical skepticism. In religious epistemology, thinkers such as Alvin Plantinga explicitly drew on Reid’s ideas to argue that belief in God can be “properly basic,” known without inferential proof in a way analogous to our belief in other minds or the external world.

However, Scottish Common Sense Realism has also faced sustained criticism. Opponents contend that appealing to “common sense” risks conservatism or cultural bias, since what is taken as self-evident can vary across societies and historical periods. Others argue that declaring certain principles immune to doubt may short-circuit philosophical inquiry, preventing deeper questions about the nature of perception, knowledge, or morality.

From a more technical perspective, critics question whether direct realism about perception can adequately explain illusion, hallucination, and scientific accounts of sensory processing. Some empiricists and later positivists argued that the common-sense framework itself should be revised in light of scientific progress, rather than treated as a fixed foundation.

Despite these objections, Scottish Common Sense Realism remains historically significant for its defense of everyday knowledge and moral belief against radical skepticism. It illustrates a distinctive strategy in modern philosophy: rather than rebuilding knowledge from the ground up through doubt, it begins from what people ordinarily take for granted and asks how these convictions can be made philosophically intelligible. Its legacy continues in contemporary debates about perception, skepticism, moral realism, and the role of common sense in philosophical method.