Skepticism (US) or scepticism (UK) is a questioning attitude or doubt toward knowledge claims that are seen as mere belief or dogma. For example, if a person is skeptical about claims made by their government about an ongoing war then the person doubts that these claims are accurate. In such cases, skeptics normally recommend not disbelief but suspension of belief, i.e. maintaining a neutral attitude that neither affirms nor denies the claim. This attitude is often motivated by the impression that the available evidence is insufficient to support the claim. Formally, skepticism is a topic of interest in philosophy, particularly epistemology.
More informally, skepticism as an expression of questioning or doubt can be applied to any topic, such as politics, religion, or pseudoscience. It is often applied within restricted domains, such as morality (moral skepticism), atheism (skepticism about the existence of God), or the supernatural. Some theorists distinguish "good" or moderate skepticism, which seeks strong evidence before accepting a position, from "bad" or radical skepticism, which wants to suspend judgment indefinitely.
Philosophical skepticism is one form of skepticism. It rejects knowledge claims that seem certain from the perspective of common sense. Radical forms of philosophical skepticism deny that "knowledge or rational belief is possible" and suggest individuals to suspend judgment on many or all controversial matters. More moderate forms claim only that nothing can be known with certainty, or that we can know little or nothing about nonempirical matters, such as whether God exists, whether human beings have free will, or whether there is an afterlife. In ancient philosophy, skepticism was understood as a way of life associated with inner peace.
Skepticism has been responsible for many important developments in science and philosophy. It has also inspired several contemporary social movements. Religious skepticism advocates for doubt concerning basic religious principles, such as immortality, providence, and revelation. Scientific skepticism advocates for testing beliefs for reliability, by subjecting them to systematic investigation using the scientific method, to discover empirical evidence for them.
Definition and semantic field Skepticism, also spelled scepticism (from the Greek , to search, to think about or look for), refers to a doubting attitude toward knowledge claims. So if a person is skeptical of their government's claims about an ongoing war then the person has doubts that these claims are true. Or being skeptical that one's favorite hockey team will win the championship means that one is uncertain about the strength of their performance. Skepticism about a claim implies that one does not believe the claim to be true. But it does not automatically follow that one should believe that the claim is false either. Instead, skeptics usually recommend a neutral attitude: beliefs about this matter should be suspended. In this regard, skepticism about a claim can be defined as the thesis that "the only justified attitude with respect to [this claim] is suspension of judgment". It is often motivated by the impression that one cannot be certain about it. This is especially relevant when there is significant expert disagreement. Skepticism is usually restricted to a claim or a field of inquiry. So religious and moral skeptics have a doubtful attitude about religious and moral doctrines. But some forms of philosophical skepticism, are wider in that they reject any form of knowledge.
Some definitions, often inspired by ancient philosophy, see skepticism not just as an attitude but as a way of life. This is based on the idea that maintaining the skeptical attitude of doubt toward most concerns in life is superior to living in dogmatic certainty, for example because such a skeptic has more happiness and peace of mind or because it is morally better. In contemporary philosophy, on the other hand, skepticism is often understood neither as an attitude nor as a way of life but as a thesis: the thesis that knowledge does not exist.
Skepticism is related to various terms. It is sometimes equated with agnosticism and relativism. However, there are slight differences in meaning. Agnosticism is often understood more narrowly as skepticism about religious questions, in particular, about the Christian doctrine. Relativism does not deny the existence of knowledge or truth but holds that they are relative to a person and differ from person to person, for example, because they follow different cognitive norms. The opposite of skepticism is dogmatism, which implies an attitude of certainty in the form of an unquestioning belief. A similar contrast is often drawn in relation to blind faith and credulity.
Types Various types of skepticism have been discussed in the academic literature. Skepticism is usually restricted to knowledge claims on one particular subject, which is why its different forms can be distinguished based on the subject. For example, religious skeptics distrust religious doctrines and moral skeptics raise doubts about accepting various moral requirements and customs. Skepticism can also be applied to knowledge in general. However, this attitude is usually only found in some forms of philosophical skepticism. A closely related classification distinguishes based on the source of knowledge, such as skepticism about perception, memory, or intuition. A further distinction is based on the degree of the skeptical attitude. The strongest forms assert that there is no knowledge at all or that knowledge is impossible. Weaker forms merely state that one can never be absolutely certain.
Some theorists distinguish between a good or healthy form of moderate skepticism in contrast to a bad or unhealthy form of radical skepticism. On this view, the "good" skeptic is a critically minded person who seeks strong evidence before accepting a position. The "bad" skeptic, on the other hand, wants to "suspend judgment indefinitely... even in the face of demonstrable truth". Another categorization focuses on the motivation for the skeptical attitude. Some skeptics have ideological motives: they want to replace inferior beliefs with better ones. Others have a more practical outlook in that they see problematic beliefs as the cause of harmful customs they wish to stop. Some skeptics have very particular goals in mind, such as bringing down a certain institution associated with the spread of claims they reject.
Philosophical skepticism is a prominent form of skepticism and can be contrasted with non-philosophical or ordinary skepticism. Ordinary skepticism involves a doubting attitude toward knowledge claims that are rejected by many. Almost everyone shows some form of ordinary skepticism, for example, by doubting the knowledge claims made by flat earthers or astrologers. Philosophical skepticism, on the other hand, is a much more radical and rare position. It includes the rejection of knowledge claims that seem certain from the perspective of common sense. Some forms of it even deny that one knows that "I have two hands" or that "the sun will come out tomorrow". It is taken seriously in philosophy nonetheless because it has proven very hard to conclusively refute philosophical skepticism.
In various fields Skepticism has been responsible for important developments in various fields, such as science, medicine, and philosophy. In science, the skeptical attitude toward traditional opinions was a key factor in the development of the scientific method. It emphasizes the need to scrutinize knowledge claims by testing them through experimentation and precise measurement. In the field of medicine, skepticism has helped establish more advanced forms of treatment by putting into doubt traditional forms that were based on intuitive appeal rather than empirical evidence. In the history of philosophy, skepticism has often played a productive role not just for skeptics but also for non-skeptical philosophers. This is due to its critical attitude that challenges the epistemological foundations of philosophical theories. This can help to keep speculation in check and may provoke creative responses, transforming the theory in question in order to overcome the problems posed by skepticism. According to Richard H. Popkin, "the history of philosophy can be seen, in part, as a struggle with skepticism". This struggle has led many contemporary philosophers to abandon the quest for absolutely certain or indubitable first principles of philosophy, which was still prevalent in many earlier periods. Skepticism has been an important topic throughout the history of philosophy and is still widely discussed today.
Philosophy
As a philosophical school or movement, skepticism arose both in ancient Greece and India. In India the Ajñana school of philosophy espoused skepticism. It was a major early rival of Buddhism and Jainism, and possibly a major influence on Buddhism. Two of the foremost disciples of the Buddha, Sariputta and Moggallāna, were initially students of the Ajñana philosopher Sanjaya Belatthiputta. A strong element of skepticism is found in Early Buddhism, most particularly in the Aṭṭhakavagga sutra. However, the total effect these philosophies had on each other is difficult to discern. Since skepticism is a philosophical attitude and a style of philosophizing rather than a position, the Ajñanins may have influenced other skeptical thinkers of India such as Nagarjuna, Jayarāśi Bhaṭṭa, and Shriharsha.
In Greece, philosophers as early as Xenophanes () expressed skeptical views, as did Democritus and a number of Sophists. Gorgias, for example, reputedly argued that nothing exists, that even if there were something we could not know it, and that even if we could know it we could not communicate it. The Heraclitean philosopher Cratylus refused to discuss anything and would merely wriggle his finger, claiming that communication is impossible since meanings are constantly changing. Socrates also had skeptical tendencies, claiming to know nothing worthwhile.
There were two major schools of skepticism in the ancient Greek and Roman world. The first was Pyrrhonism, founded by Pyrrho of Elis (). The second was Academic Skepticism, so-called because its two leading defenders, Arcesilaus () who initiated the philosophy, and Carneades (), the philosophy's most famous proponent, were heads of Plato's Academy. Pyrrhonism's aims are psychological. It urges suspension of judgment () to achieve mental tranquility (). The Academic Skeptics denied that knowledge is possible (). The Academic Skeptics claimed that some beliefs are more reasonable or probable than others, whereas Pyrrhonian skeptics argue that equally compelling arguments can be given for or against any disputed view. Nearly all the writings of the ancient skeptics are now lost. Most of what we know about ancient skepticism is from Sextus Empiricus, a Pyrrhonian skeptic who lived in . His works contain a lucid summary of stock skeptical arguments.