Philosophical skepticism (UK spelling: scepticism; from Greek σκέψις skepsis, "inquiry") is a philosophical school of thought that questions the possibility of certainty in knowledge. Skeptic philosophers from different historical periods adopted different principles and arguments, but their ideology can be generalized as either (1) the denial of possibility of all knowledge or (2) the suspension of judgement due to the inadequacy of evidence.
Skepticism is not a single position but covers a range of different positions. In the ancient world there were two main skeptical traditions. Academic skepticism took the dogmatic position that knowledge was not possible; Pyrrhonian skeptics refused to take a dogmatic position on any issue—including skepticism. Radical skepticism ends in the paradoxical claim that one cannot know anything—including that one cannot know about knowing anything.
Skepticism can be classified according to its scope. Local skepticism involves being skeptical about particular areas of knowledge, e.g. moral skepticism, skepticism about the external world, or skepticism about other minds, whereas global skepticism is skeptical about the possibility of any knowledge at all.
Skepticism can also be classified according to its method. In the Western tradition there are two basic approaches to skepticism. Cartesian skepticism —named somewhat misleadingly after René Descartes, who was not a skeptic but used some traditional skeptical arguments in his Meditations to help establish his rationalist approach to knowledge— attempts to show that any proposed knowledge claim can be doubted. Agrippan skepticism focuses on the process of justification rather than the possibility of doubt. According to this view there are three ways in which one might attempt to justify a claim but none of them are adequate: one can keep on providing further justification but this leads to an infinite regress; one can stop at a dogmatic assertion; or one can argue in circular reasoning, never reaching a viable conclusion.
Philosophical skepticism is distinguished from methodological skepticism in that philosophical skepticism is an approach that questions the possibility of certainty in knowledge, whereas methodological skepticism is an approach that subjects all knowledge claims to scrutiny with the goal of sorting out true from false claims.
Philosophical skepticism begins with the claim that the skeptic currently does not have knowledge. Some adherents maintain that knowledge is, in theory, possible. It could be argued that Socrates held that view. He appears to have thought that if people continue to ask questions they might eventually come to have knowledge; but that they did not have it yet. Some skeptics have gone further and claimed that true knowledge is impossible, for example the Academic school in Ancient Greece well after the time of Carneades. A third skeptical approach would be neither to accept nor reject the possibility of knowledge.
Skepticism can be either about everything or about particular areas. A 'global' skeptic argues that he does not absolutely know anything to be either true or false. Academic global skepticism has great difficulty in supporting this claim while maintaining philosophical rigor, since it seems to require that nothing can be known—except for the knowledge that nothing can be known, though in its probabilistic form it can use and support the notion of weight of evidence. Thus, some probabilists avoid extreme skepticism by maintaining that they merely are 'reasonably certain' (or 'largely believe') some things are real or true. As for using probabilistic arguments to defend skepticism, in a sense this enlarges or increases skepticism, while the defence of empiricism by Empiricus weakens skepticism and strengthens dogmatism by alleging that sensory appearances are beyond doubt. Much later, Kant would re-define "dogmatism" to make indirect realism about the external world seem objectionable. While many Hellenists, outside of Empiricus, would maintain that everyone who is not sceptical about everything is a dogmatist, this position would seem too extreme for most later philosophers.
Nevertheless, a Pyrrhonian global skeptic labors under no such modern constraint, since Pyrrho only alleged that he, personally, did not know anything. He made no statement about the possibility of knowledge. Nor did Arcesilaus feel bound, since he merely corrected Socrates's "I only know that I know nothing" by adding "I don't even know that", thus more fully rejecting dogmatism.
Local skeptics deny that people do or can have knowledge of a particular area. They may be skeptical about the possibility of one form of knowledge without doubting other forms. Different kinds of local skepticism may emerge, depending on the area. A person may doubt the truth value of different types of journalism, for example, depending on the types of media they trust.
Skepticism, as an epistemological argument, poses the question of whether knowledge, in the first place, is possible. Skeptics argue that the belief in something does not necessarily justify an assertion of knowledge of it. In this, skeptics oppose dogmatic foundationalism, which states that there have to be some basic positions that are self-justified or beyond justification, without reference to others. (One example of such foundationalism may be found in Spinoza's Ethics.) The skeptical response to this can take several approaches. First, claiming that "basic positions" must exist amounts to the logical fallacy of argument from ignorance combined with the slippery slope.
Among other arguments, skeptics used Agrippa's trilemma, named after Agrippa the Sceptic, to claim no certain belief could be achieved. Foundationalists have used the same trilemma as a justification for demanding the validity of basic beliefs.
This skeptical approach is rarely taken to its pyrrhonean extreme by most practitioners. Several modifications have arisen over the years, including the following :
Fictionalism would not claim to have knowledge but will adhere to conclusions on some criterion such as utility, aesthetics, or other personal criteria without claiming that any conclusion is actually "true".
Philosophical fideism (as opposed to religious Fideism) would assert the truth of some propositions, but does so without asserting certainty.
Some forms of pragmatism would accept utility as a provisional guide to truth but not necessarily a universal decision-maker.
There are two different categories of epistemological skepticism, which can be referred to as mitigated and unmitigated skepticism. The two forms are contrasting but are still true forms of skepticism. Mitigated skepticism does not accept "strong" or "strict" knowledge claims but does, however, approve specific weaker ones. These weaker claims can be assigned the title of "virtual knowledge", but must be to justified belief. Unmitigated skepticism rejects both claims of virtual knowledge and strong knowledge. Characterising knowledge as strong, weak, virtual or genuine can be determined differently depending on a person's viewpoint as well as their characterisation of knowledge.
Most philosophies have weaknesses and can be criticized and this is a general principle of progression in philosophy. The philosophy of skepticism asserts that no truth is knowable, or that truth is at best only probable. An argument commonly made but limited to science is that the scientific method asserts only probable findings, because the number of cases tested is always limited and because the tests constitute perceptual observations.
A criticism of skepticism generally is that there is a contradiction involved in claiming that the proposition that “no truth is knowable” is knowably true. The here is one hand argument is another relatively simple criticism that reverses the skeptic's proposals and supports common sense.
Pierre Le Morvan (2011) has distinguished between three broad philosophical approaches to skepticism. The first he calls the "Foil Approach." Skepticism is treated as a problem to be solved, or challenge to be met, or threat to be parried; its value, if any, derives from its role as a foil. It clarifies by contrast, and so illuminates what is required for knowledge and justified belief. The second he calls the "Bypass Approach" according to which skepticism is bypassed as a central concern of epistemology. Le Morvan advocates a third approach—he dubs it the "Health Approach"—that explores when skepticism is healthy and when it is not, or when it is virtuous and when it is vicious.
A skeptical hypothesis is a hypothetical situation which can be used in an argument for skepticism about a particular claim or class of claims. Usually the hypothesis posits the existence of a deceptive power that deceives our senses and undermines the justification of knowledge otherwise accepted as justified. Skeptical hypotheses have received much attention in modern Western philosophy.
The first skeptical hypothesis in modern Western philosophy appears in René Descartes' Meditations on First Philosophy. At the end of the first Meditation Descartes writes: "I will suppose... that some evil demon of the utmost power and cunning has employed all his energies to deceive me."
The Western tradition of systematic skepticism goes back at least as far as Pyrrho of Elis (b. circa 360 BCE) and arguably to Xenophanes (b. circa 570 BCE). Parts of skepticism also appear among the "5th century sophists [who] develop forms of debate which are ancestors of skeptical argumentation. They take pride in arguing in a persuasive fashion for both sides of an issue." According to an account of Pyrrho's life by his student Timon of Phlius, Pyrrho extolled a way to become happy and tranquil.
"Whoever wants to live well (eudaimonia) must consider these three questions: First, how are pragmata (ethical matters, affairs, topics) by nature? Secondly, what attitude should we adopt towards them? Thirdly, what will be the outcome for those who have this attitude?" Pyrrho's answer is that "As for pragmata they are all adiaphora (undifferentiated by a logical differentia), astathmēta (unstable, unbalanced, not measurable), and anepikrita (unjudged, unfixed, undecidable). Therefore, neither our sense-perceptions nor our doxai (views, theories, beliefs) tell us the truth or lie; so we certainly should not rely on them. Rather, we should be adoxastous (without views), aklineis (uninclined toward this side or that), and akradantous (unwavering in our refusal to choose), saying about every single one that it no more is than it is not or it both is and is not or it neither is nor is not.
The main principle of Pyrrho's thought is expressed by the word acatalepsia, which connotes the ability to suspend judgment between doctrines regarding the truth of things in their own nature as against every dogma a contradiction may be advanced with equal justification.
Pyrrhonists are not "skeptics" in the modern, common sense of the term, meaning prone to disbelief. They had the goal of αταραξια (ataraxia – peace of mind), and pitted one dogma against another to undermine belief in dogmatic propositions. The objective was to produce in the student a state of epoché towards ideas about non-evident matters. Since no one can observe or otherwise experience causation, external world (its "externality"), ultimate purpose of the universe or life, justice, divinity, soul, etc., they declared no need to have beliefs about such things. The Pyrrhonists pointed out that people ignorant of such things get by just fine before learning about them. They further noted that science does not require belief and that faith in intelligible realities is different from pragmatic convention for the sake of experiment. For each intuitive notion (e.g. the existence of an external world), the Pyrrhonists cited a contrary opinion to negate it. They added that consensus indicates neither truth nor even probability.
Pyrrho's thinking subsequently influenced the Platonic Academy, arising first in the Academic skepticism of the Middle Academy under Arcesilaus (c. 315 – 241 BCE) and then the New Academy under Carneades (c. 213–129 BCE). Clitomachus, a student of Carneades, interpreted his teacher's philosophy as suggesting an early probabilistic account of knowledge. The Roman politician and philosopher, Cicero, also seems to have been a supporter of the probabilistic position attributed to the New Academy, even though a return to a more dogmatic orientation of the school was already beginning to take place.
In the centuries to come, the words Academician and Pyrrhonist would often be used to mean generally skeptic, often ignoring historical changes and distinctions between denial of knowledge and avoidance of belief, between degree of belief and absolute belief, and between possibility and probability.
The works of Sextus Empiricus (c. 200 CE) are the main surviving account of ancient Pyrrhonism. By Sextus' time, the Academy had ceased to be a skeptical or probabilistic school, and argued in a different direction, incorporating aspects of empiricism into the basis for evaluating knowledge, but without the insistence on experience as the absolute standard of it. Sextus' empiricism was limited to the "absolute minimum" already mentioned — that there seem to be appearances. Sextus compiled and further developed the Pyrrhonists' skeptical arguments, most of which were directed against the Stoics but included arguments against all of the schools of Hellenistic philosophy, including the Academic skeptics.
A common anti-skeptical argument is that if one knows nothing, one cannot know that one knows nothing, and so may know something after all. However, such an argument is effective only against the complete denial of the possibility of knowledge. Sextus argued that claims to either know or not to know were both dogmatic and as such Pyrrhonists claimed neither. Instead, they claimed to be continuing to search for something that might be knowable.
Sextus, as the most systematic author of the works by Hellenistic sceptics which have survived, noted that there are at least ten modes of skepticism. These modes may be broken down into three categories: one may be skeptical of the subjective perceiver, of the objective world, and the relation between perceiver and the world. His arguments are as follows.
Subjectively, both the powers of the senses and of reasoning may vary among different people. And since knowledge is a product of one or the other, and since neither are reliable, knowledge would seem to be in trouble. For instance, a color-blind person sees the world quite differently from everyone else. Moreover, one cannot even give preference on the basis of the power of reason, i.e., by treating the rational animal as a carrier of greater knowledge than the irrational animal, since the irrational animal is still adept at navigating their environment, which suggests the ability to "know" about some aspects of the environment.
Secondly, the personality of the individual might also influence what they observe, since (it is argued) preferences are based on sense-impressions, differences in preferences can be attributed to differences in the way that people are affected by the object. (Empiricus:56)
Third, the perceptions of each individual sense seemingly have nothing in common with the other senses: i.e., the color "red" has little to do with the feeling of touching a red object. This is manifest when our senses "disagree" with each other: for example, a mirage presents certain visible features, but is not responsive to any other kind of sense. In that case, our other senses defeat the impressions of sight. But one may also be lacking enough powers of sense to understand the world in its entirety: if one had an extra sense, then one might know of things in a way that the present five senses are unable to advise us of. Given that our senses can be shown to be unreliable by appealing to other senses, and so our senses may be incomplete (relative to some more perfect sense that one lacks), then it follows that all of our senses may be unreliable. (Empiricus:58)
Fourth, our circumstances when one perceives anything may be either natural or unnatural, i.e., one may be either in a state of wakefulness or sleep. But it is entirely possible that things in the world really are exactly as they appear to be to those in unnatural states (i.e., if everything were an elaborate dream). (Empiricus:59)
One can have reasons for doubt that are based on the relationship between objective "facts" and subjective experience. The positions, distances, and places of objects would seem to affect how they are perceived by the person: for instance, the portico may appear tapered when viewed from one end, but symmetrical when viewed at the other; and these features are different. Because they are different features, to believe the object has both properties at the same time is to believe it has two contradictory properties. Since this is absurd, one must suspend judgment about what properties it possesses due to the contradictory experiences. (Empiricus:63)
One may also observe that the things one perceives are, in a sense, polluted by experience. Any given perception—say, of a chair—will always be perceived within some context or other (i.e., next to a table, on a mat, etc.) Since this is the case, one often only speaks of ideas as they occur in the context of the other things that are paired with it, and therefore, one can never know of the true nature of the thing, but only how it appears to us in context. (Empiricus: 64)
Along the same lines, the skeptic may insist that all things are relative, by arguing that:
Finally, one has reason to disbelieve that one knows anything by looking at problems in understanding objects by themselves. Things, when taken individually, may appear to be very different from when they are in mass quantities: for instance, the shavings of a goat's horn are white when taken alone, yet the horn intact is black.
His most notable writings on Skepticism occurred in an essay written mostly in 1575–1576, "Apologie de Raimond Sebond," when he was reading Sextus Empiricus and trying to translate Raimond Sebond's writing, including his proof of Christianity's natural existence. The reception to Montaigne's translations included some criticisms of Sebond's proof. Montaigne responded to some of them in Apologie, including a defense for Sebond's logic that is skeptical in nature and similar to Pyrrhonism. His refutation is as follows:
Marin Mersenne was an author, a mathematician, a scientist, and a philosopher. He wrote in defense of science and Christianity against atheists and Pyrrhonists before retiring to encourage development of science and the "new philosophy," which includes philosophers like Gassendi, Descartes, Galileo, and Hobbes. A major work of his in relation to Skepticism is La Verité des Sciences, in which he argues that although we may not be able to know the true nature of things, we can still formulate certain laws and rules for sense-perceptions through science.
Additionally, he points out that we do not doubt everything because:
A Pyrrhonist might refute these points by saying that senses deceive, and thus knowledge turns into infinite regress or circular logic. Thus Mersenne argues that this cannot be the case, since commonly agreed upon rules of thumb can be hypothesized and tested over time to ensure that they continue to hold.
Furthermore, if everything can be doubted, the doubt can also be doubted, so on and so forth. Thus, according to Mersenne, something has to be true. Finally, Mersenne writes about all the mathematical, physical, and other scientific knowledge that is true by repeated testing, and has practical use value. Notably, Mersenne was one of the few philosophers who accepted Hobbes' radical ideology—he saw it as a new science of man.
During his long stay in Paris, Thomas Hobbes was actively involved in the circle of major skeptics like Gassendi and Mersenne who focus on the study of skepticism and epistemology. Unlike his fellow skeptic friends, Hobbes never treated skepticism as a main topic for discussion in his works. Nonetheless, Hobbes was still labeled as a religious skeptic by his contemporaries for raising doubts about Mosaic authorship of the Pentateuch and his political and psychological explanation of the religions. Although Hobbes himself did not go further to challenge other religious principles, his suspicion for the Mosaic authorship did significant damage to the religious traditions and paved the way for later religious skeptics like Spinoza and Isaac La Peyrère to further question some of the fundamental beliefs of the Judeo-Christian religious system. Hobbes' answer to skepticism and epistemology was innovatively political: he believed that moral knowledge and religious knowledge were in their nature relative, and there was no absolute standard of truth governing them. As a result, it was out of political reasons that certain truth standards about religions and ethics were devised and established in order to form functioning government and stable society.
Baruch Spinoza was among the first European philosophers who were religious skeptics. He was quite familiar with the philosophy of Descartes and unprecedentedly extended the application of the Cartesian method to the religious context by analyzing religious texts with it. Spinoza sought to dispute the knowledge-claims of the Judeo-Christian-Islamic religious system by examining its two foundations: the Scripture and the Miracles. He claimed that all Cartesian knowledge, or the rational knowledge should be accessible to the entire population. Therefore, the Scriptures, aside from those by Jesus, should not be considered the secret knowledge attained from God but just the imagination of the prophets. The Scriptures, as a result of this claim, could not serve as a base for knowledge and were reduced to simple ancient historical texts. Moreover, Spinoza also rejected the possibility for the Miracles by simply asserting that people only considered them miraculous due to their lack of understanding of the nature. By rejecting the validity of the Scriptures and the Miracles, Spinoza demolished the foundation for religious knowledge-claim and established his understanding of the Cartesian knowledge as the sole authority of knowledge-claims. Despite being deeply-skeptical of the religions, Spinoza was in fact exceedingly anti-skeptical towards reason and rationality. He steadfastly confirmed the legitimacy of reason by associating it with the acknowledgement of God, and thereby skepticism with the rational approach to knowledge was not due to problems with the rational knowledge but from the fundamental lack of understanding of God. Spinoza's religious skepticism and anti-skepticism with reason thus helped him transform epistemology by separating the theological knowledge-claims and the rational knowledge-claims.
Pierre Bayle was a French philosopher in the late 17th century that was described by Richard Popkin to be a "supersceptic" who carried out the sceptic tradition to the extreme. Bayle was born in a Calvinist family in Carla-Bayle, and during the early stage of his life, he converted into Catholicism before returning to Calvinism. This conversion between religions caused him to leave France for the more religiously tolerant Holland where he stayed and worked for the rest of his life.
Bayle believed that truth cannot be obtained through reason and that all human endeavor to acquire absolute knowledge would inevitably lead to failure. Bayle's main approach was highly skeptical and destructive: he sought to examine and analyze all existing theories in all fields of human knowledge in order to show the faults in their reasoning and thus the absurdity of the theories themselves. In his magnum opus, Dictionnaire Historique et Critique (Historical and Critical Dictionary), Bayle painstakingly identified the logical flaws in several works throughout the history in order to emphasize the absolute futility of rationality. Bayle's complete nullification of reason led him to conclude that faith is the final and only way to truth.
Bayle's real intention behind his extremely destructive works remained controversial. Some described him to be a Fideist, while others speculated him to be a secret Atheist. However, no matter what his original intention was, Bayle did cast significant influence on the upcoming Age of Enlightenment with his destruction of some of the most essential theological ideas and his justification of religious tolerance Atheism in his works.
Immanuel Kant (1724–1804) tried to provide a ground for empirical science against David Hume's skeptical treatment of the notion of cause and effect. Hume (1711–1776) argued that for the notion of cause and effect no analysis is possible which is also acceptable to the empiricist program primarily outlined by John Locke (1632–1704). But, Kant's attempt to give a ground to knowledge in the empirical sciences at the same time cut off the possibility of knowledge of any other knowledge, especially what Kant called "metaphysical knowledge". So, for Kant, empirical science was legitimate, but metaphysics and philosophy was mostly illegitimate. The most important exception to this demarcation of the legitimate from the illegitimate was ethics, the principles of which Kant argued can be known by pure reason without appeal to the principles required for empirical knowledge. Thus, with respect to metaphysics and philosophy in general (ethics being the exception), Kant was a skeptic. This skepticism as well as the explicit skepticism of G. E. Schulze gave rise to a robust discussion of skepticism in classical German philosophy, especially by Hegel. Kant's idea was that the real world (the noumenon or thing-in-itself) was inaccessible to human reason (though the empirical world of nature can be known to human understanding) and therefore we can never know anything about the ultimate reality of the world. Hegel argued against Kant that although Kant was right that using what Hegel called "finite" concepts of "the understanding" precluded knowledge of reality, we were not constrained to use only "finite" concepts and could actually acquire knowledge of reality using "infinite concepts" that arise from self-consciousness.
Because Richard Popkin was one of the founding fathers of study in this area, the account of the history of Skepticism in his books are accepted as the standard. However, recent scholars have been suggesting an addition to Popkin's account. Instead of centering the history of Skepticism around specific figures who wrote key skeptical works, Skepticism is proposed to be a continuous engagement with works by ancients like Sextus Empiricus to modern thinkers like Hume. The engagement with previous works were probably due to unwanted doubts about accepted episteme instead of purely due to classical writings becoming available at any specific time.
Ajñana (literally 'non-knowledge') were the skeptical school of ancient Indian philosophy. It was a śramaṇa movement and a major rival of early Buddhism and Jainism. They have been recorded in Buddhist and Jain texts. They held that it was impossible to obtain knowledge of metaphysical nature or ascertain the truth value of philosophical propositions; and even if knowledge was possible, it was useless and disadvantageous for final salvation.
The historical Buddha asserted certain doctrines as true, such as the possibility of nirvana; however, he also upheld a form of skepticism with regards to certain questions which he left "un-expounded" (avyākata) and some he saw as "incomprehensible" (acinteyya). Because the Buddha saw these questions (which tend to be of metaphysical topics) as unhelpful on the path and merely leading to confusion and "a thicket of views", he promoted suspension of judgment towards them. This allowed him to carve out an epistemic middle way between what he saw as the extremes of claiming absolute objectivity (associated with the claims to omniscience of the Jain Mahavira) and extreme skepticism (associated with the Ajñana thinker Sanjaya Belatthiputta).
Later Buddhist Philosophy remained highly skeptical of Indian metaphysical arguments. The Buddhist philosopher Nagarjuna in particular has been seen as the founder of the Madhyamaka school, which has been in turn compared with Greek Skepticism. Nagarjuna's statement that he has "no thesis" (pratijña) has parallels in the statements of Sextus Empiricus of having "no position". Nagarjuna famously opens his magnum opus, the Mulamadhyamakakarika, with the statement that the Buddha claimed that true happiness was found through dispelling 'vain thinking' (prapañca, also "conceptual proliferation").
...in both early Buddhism and in the Skeptics one can find the view put forward that man's pursuit of happiness, the highest good, is obstructed by his tenacity in holding ungrounded and unnecessary opinions about all manner of things. Much of Buddhist philosophy, I shall argue, can be seen as an attempt to break this habit of holding on to opinions.
The Cārvāka (Sanskrit: चार्वाक) school of materialism, also known as Lokāyata, is a distinct branch of Indian philosophy. The school is named after Cārvāka, author of the Bārhaspatya-sūtras and was founded in approximately 500 BC. Cārvāka is classified as a "heterodox" (nāstika) system, characterized as a materialistic and atheistic school of thought. This school was also known for being strongly skeptical of the claims of Indian religions, such as reincarnation and karma.
While Jain philosophy claims that is it possible to achieve omniscience, absolute knowledge (Kevala Jnana), at the moment of enlightenment, their theory of anekāntavāda or 'many sided-ness', also known as the principle of relative pluralism, allows for a practical form of skeptical thought regarding philosophical and religious doctrines (for un-enlightened beings, not all-knowing arihants).
According to this theory, the truth or the reality is perceived differently from different points of view, and that no single point of view is the complete truth. Jain doctrine states that, an object has infinite modes of existence and qualities and, as such, they cannot be completely perceived in all its aspects and manifestations, due to inherent limitations of the humans. Anekāntavāda is literally the doctrine of non-onesidedness or manifoldness; it is often translated as "non-absolutism". Syādvāda is the theory of conditioned predication which provides an expression to anekānta by recommending that epithet “Syād” be attached to every expression. Syādvāda is not only an extension of Anekānta ontology, but a separate system of logic capable of standing on its own force. As reality is complex, no single proposition can express the nature of reality fully. Thus the term “syāt” should be prefixed before each proposition giving it a conditional point of view and thus removing any dogmatism in the statement. For Jains, fully enlightened beings are able to see reality from all sides and thus have ultimate knowledge of all things. This idea of omniscience was criticized by Buddhists such as Dharmakirti.
Zhuang Zhou (莊子，"Master Zhuang") was a famous ancient Chinese Taoism philosopher during the Hundred Schools of Thought period. Zhuang Zhou demonstrated his skeptical thinking through several anecdotes in the preeminent work Zhuangzi that was attributed to him:
Through these anecdotes in Zhuangzi, Zhuang Zhou indicated his belief in the limitation of language and human communication and the inaccessibility of universal truth which established himself as an skeptic. But Zhuang Zhou was by no means a radical skeptic, since he only applied skeptical methods partially in some of his arguments to demonstrate his Taoism beliefs while adopting these Taoism beliefs in a dogmatic fashion.
Wang Chong (王充) was the leading figure of the skeptic branch of the Confucianism school in China during the first century AD. He introduced a method of rational critique and applied it to the wide-spread dogmatism thinking of his age like phenomenology (the main contemporary Confucianism ideology that linked all natural phenomena with human ethics), state-led cults, and popular superstition. His own philosophy incorporated both Taoism and Confucianism thinkings, and it was based on a secular, rational practice of developing hypotheses based on natural events to explain the universe which exemplified a form of naturalism that resembled the philosophical idea of Epicureans like Lucretius.
The Incoherence of the Philosophers, written by the scholar Al-Ghazali (1058–1111), marks a major turn in Islamic epistemology. His encounter with skepticism led Ghazali to embrace a form of theological occasionalism, or the belief that all causal events and interactions are not the product of material conjunctions but rather the immediate and present will of God. While he himself was a critic of the philosophers, Ghazali was a master in the art of philosophy and had immensely studied the field. After such a long education in philosophy, as well as a long process of reflection, he had criticized the philosophical method.
In the autobiography Ghazali wrote towards the end of his life, The Deliverance From Error (Al-munqidh min al-ḍalāl ), Ghazali recounts how, once a crisis of epistemological skepticism was resolved by "a light which God Most High cast into my breast...the key to most knowledge," he studied and mastered the arguments of Kalam, Islamic philosophy, and Ismailism. Though appreciating what was valid in the first two of these, at least, he determined that all three approaches were inadequate and found ultimate value only in the mystical experience and spiritual insight he attained as a result of following Sufi practices. William James, in Varieties of Religious Experience, considered the autobiography an important document for "the purely literary student who would like to become acquainted with the inwardness of religions other than the Christian", comparing it to recorded personal religious confessions and autobiographical literature in the Christian tradition.
Recordings of Aztec philosophy suggest that the elite classes believed in an essentially panentheistic worldview, in which teotl represents an unified, underlying universal force. Human beings cannot truly perceive teotl due to its chaotic, constantly changing nature, just the "masks"/facets it is manifested as.
Barry Stroud (; born 1935) is a Canadian philosopher known for his work on philosophical skepticism, David Hume, and Ludwig Wittgenstein, among other topics.Cartesian doubt
Cartesian Doubt is a form of methodological skepticism associated with the writings and methodology of René Descartes (March 31,1596–Feb 11, 1650). Cartesian doubt is also known as Cartesian skepticism, methodic doubt, methodological skepticism, universal doubt, systematic doubt or hyperbolic doubt.
Cartesian doubt is a systematic process of being skeptical about (or doubting) the truth of one's beliefs, which has become a characteristic method in philosophy. Additionally, Descartes's method has been seen by many as the root of the modern scientific method. This method of doubt was largely popularized in Western philosophy by René Descartes, who sought to doubt the truth of all his beliefs in order to determine which beliefs he could be certain were true. It is the basis for Descartes' statement, "Cogito ergo sum" ("I think, therefore I am"). Of course, Descartes never actually wrote "cogito ergo sum,' instead, he wrote in his native French, "Je pense, donc je suis."
Methodological skepticism is distinguished from philosophical skepticism in that methodological skepticism is an approach that subjects all knowledge claims to scrutiny with the goal of sorting out true from false claims, whereas philosophical skepticism is an approach that questions the possibility of certain knowledge.Celia Green
Celia Elizabeth Green (born 26 November 1935) is a British writer on philosophical skepticism and psychology.Certainty
Certainty is perfect knowledge that has total security from error, or the mental state of being without doubt.
Objectively defined, certainty is total continuity and validity of all foundational inquiry, to the highest degree of precision. Something is certain only if no skepticism can occur. Philosophy (at least, historical Cartesian philosophy) seeks this state.Charvaka
Charvaka (IAST: Cārvāka), originally known as Lokāyata and Bārhaspatya, is an ancient school of Indian materialism. Charvaka holds direct perception, empiricism, and conditional inference as proper sources of knowledge, embraces philosophical skepticism and rejects Vedas, Vedic ritualism, and supernaturalism.Ajita Kesakambali is credited as the forerunner of the Charvakas, while Brihaspati is usually referred to as the founder of Charvaka or Lokāyata philosophy. Much of the primary literature of Charvaka, the Barhaspatya sutras (ca. 600 BCE), are missing or lost. Its teachings have been compiled from historic secondary literature such as those found in the shastras, sutras, and the Indian epic poetry as well as in the dialogues of Gautama Buddha and from Jain literature.One of the widely studied principles of Charvaka philosophy was its rejection of inference as a means to establish valid, universal knowledge, and metaphysical truths. In other words, the Charvaka epistemology states that whenever one infers a truth from a set of observations or truths, one must acknowledge doubt; inferred knowledge is conditional.Charvaka is categorized as a heterodox school of Indian philosophy. It is considered an example of atheistic schools in the Hindu tradition.Here is one hand
Here is one hand is an epistemological argument created by George Edward Moore in reaction against philosophical skepticism and in support of common sense.
The argument takes the following form:
Here is one hand,
And here is another.
There are at least two external objects in the world.
Therefore, an external world exists.Katalepsis
Katalepsis (Greek: κατάληψις, "grasping") in Stoic philosophy, meant comprehension. To the Stoic philosophers, katalepsis was an important premise regarding one's state of mind as it relates to grasping fundamental philosophical concepts, and it represents the Stoic solution to the problem of the criterion.Local skepticism
Local skepticism is the view that one cannot possess knowledge in some particular domain. It contrasts with global skepticism (also known as absolute skepticism or universal skepticism), the view that one cannot know anything at all.Monimus
Monimus (; Greek: Μόνιμος; 4th century BCE) of Syracuse, was a Cynic philosopher who endorsed philosophical skepticism, denying that there was a criterion of truth.Obscurantism
Obscurantism ( and ) is the practice of deliberately presenting information in an imprecise and recondite manner, often designed to forestall further inquiry and understanding. There are two historical and intellectual denotations of Obscurantism: (1) the deliberate restriction of knowledge—opposition to disseminating knowledge; and, (2) deliberate obscurity—an abstruse style (as in literature and art) characterized by deliberate vagueness.The term obscurantism derives from the title of the 16th-century satire Epistolæ Obscurorum Virorum (1515–19, Letters of Obscure Men), that was based upon the intellectual dispute between the German humanist Johann Reuchlin and the monk Johannes Pfefferkorn of the Dominican Order, about whether or not all Jewish books should be burned as un-Christian heresy. Earlier, in 1509, the monk Pfefferkorn had obtained permission from Maximilian I, Holy Roman Emperor (1486–1519), to burn all copies of the Talmud (Jewish law and Jewish ethics) known to be in the Holy Roman Empire (AD 926–1806); the Letters of Obscure Men satirized the Dominican arguments for burning "un-Christian" works.
In the 18th century, Enlightenment philosophers applied the term obscurantist to any enemy of intellectual enlightenment and the liberal diffusion of knowledge. In the 19th century, in distinguishing the varieties of obscurantism found in metaphysics and theology from the "more subtle" obscurantism of the critical philosophy of Immanuel Kant, and of modern philosophical skepticism, Friedrich Nietzsche said: "The essential element in the black art of obscurantism is not that it wants to darken individual understanding, but that it wants to blacken our picture of the world, and darken our idea of existence."On Certainty
On Certainty (German: Über Gewissheit, original spelling Über Gewißheit) is a philosophical book composed from notes written by Ludwig Wittgenstein over four separate periods in the eighteen months before his death on 29 April 1951. He left his initial notes at the home of Elizabeth Anscombe, who linked them by theme with later passages in Wittgenstein's personal notebooks and (with G. H. von Wright), compiled them into a German/English parallel text book published in 1969. The translators were Denis Paul and Anscombe herself. (The editors also numbered and grouped the 676 passages; citations to the work are standardly given as OC1..OC676 rather than by page number.)
The book's concerns are largely epistemological, a recurrent theme being that there are some things which must be exempt from doubt in order for human practices to be possible, including the activity of raising doubts: "A doubt that doubted everything would not be a doubt" (OC450). The book takes as its starting point the 'here is one hand' argument made by G. E. Moore and examines the role of knowledge claims in human language, particularly of "certain ('gewisser') empirical propositions", what are now called Moorean propositions or Moorean certainties.
An important outcome is Wittgenstein's claim that all doubt is embedded in underlying beliefs and therefore the most radical forms of doubt must be rejected since they form a contradiction within the system that expressed them. Wittgenstein also sketched novel refutations of philosophical skepticism in various guises.Problem of other minds
The problem of other minds is a philosophical problem traditionally stated as the following epistemological challenge raised by the skeptic: Given that I can only observe the behavior of others, how can I know that others have minds? It is a central issue of the philosophical idea known as solipsism: the notion that for any person only one's own mind is known to exist. Solipsism maintains that no matter how sophisticated someone's behavior is, behavior on its own does not guarantee the presence of mentality.Pyrrho
Pyrrho of Elis (; Ancient Greek: Πύρρων ὁ Ἠλεῖος, romanized: Pyrrhо̄n ho Ēleios; c. 360 – c. 270 BC) was a Greek philosopher of Classical antiquity and is credited as being the first Greek skeptic philosopher and founder of Pyrrhonism.Pyrrhonism
Pyrrhonism is a school of philosophical skepticism founded by Pyrrho in the fourth century BCE. It is best known through the surviving works of Sextus Empiricus, writing in the late second century or early third century CE.Reliabilism
Reliabilism, a category of theories in the philosophical discipline of epistemology, has been advanced as a theory both of justification and of knowledge. Process reliabilism has been used as an argument against philosophical skepticism, such as the brain in a vat thought experiment.
Process reliabilism is a form of epistemic externalism.Self-refuting idea
Self-refuting ideas or self-defeating ideas are ideas or statements whose falsehood is a logical consequence of the act or situation of holding them to be true. Many ideas are called self-refuting by their detractors, and such accusations are therefore almost always controversial, with defenders stating that the idea is being misunderstood or that the argument is invalid. For these reasons, none of the ideas below are unambiguously or incontrovertibly self-refuting. These ideas are often used as axioms, which are definitions taken to be true (tautological assumptions), and cannot be used to test themselves, for doing so would lead to only two consequences: consistency (circular reasoning) or exception (self-contradiction). It is important to know that the conclusion of an argument that is self-refuting is not necessarily false, since it could be supported by another, more valid, argument.Skepticism
Skepticism (American English) or scepticism (British English, Australian English, and Canadian English) is generally a questioning attitude or doubt towards one or more items of putative knowledge or belief or dogma. It is often directed at domains, such as the supernatural, morality (moral skepticism), theism (skepticism about the existence of God), or knowledge (skepticism about the possibility of knowledge, or of certainty). Formally, skepticism as a topic occurs in the context of philosophy, particularly epistemology, although it can be applied to any topic such as politics, religion, and pseudoscience.
Philosophical skepticism comes in various forms. Radical forms of skepticism deny that knowledge or rational belief is possible and urge us to suspend judgment on many or all controversial matters. More moderate forms of skepticism claim only that nothing can be known with certainty, or that we can know little or nothing about the big question in life, such as whether God exists or whether there is an afterlife. Religious skepticism is "doubt concerning basic religious principles (such as immortality, providence, and revelation)". Scientific skepticism concerns testing beliefs for reliability, by subjecting them to systematic investigation using the scientific method, to discover empirical evidence for them.Spectrum of theistic probability
Popularized by Richard Dawkins in The God Delusion, the spectrum of theistic probability is a way of categorizing one's belief regarding the probability of the existence of a deity.Truth
Truth is most often used to mean being in accord with fact or reality, or fidelity to an original or standard. Truth is also sometimes defined in modern contexts as an idea of "truth to self", or authenticity.
Truth is usually held to be opposite to falsehood, which, correspondingly, can also suggest a logical, factual, or ethical meaning. The concept of truth is discussed and debated in several contexts, including philosophy, art, theology, and science. Most human activities depend upon the concept, where its nature as a concept is assumed rather than being a subject of discussion; these include most of the sciences, law, journalism, and everyday life. Some philosophers view the concept of truth as basic, and unable to be explained in any terms that are more easily understood than the concept of truth itself. To some, truth is viewed as the correspondence of language or thought to an independent reality, in what is sometimes called the correspondence theory of truth.
Various theories and views of truth continue to be debated among scholars, philosophers, and theologians. Language is a means by which humans convey information to one another. The method used to determine whether something is a truth is termed a criterion of truth. There are varying stances on such questions as what constitutes truth: what things are truthbearers capable of being true or false; how to define, identify, and distinguish truth; what roles do faith and empirical knowledge play; and whether truth can be subjective or is objective: relative truth versus absolute truth.