Skepticism

Skepticism (Scepticism in the United Kingdom) is an epistemology that suspends judgement about certain kinds of beliefs through a method or attitude characterized by systematic doubt about claims usually taken for granted. Traditionally in the branch of philosophy called epistemology Justified True Beliefs are what constitute knowledge. Skepticism questions knowledge in other words with some skeptics going so far as to question even foundational beliefs like the human sensory system. Questioning and thus opposing the very important empirical character and underpinnings of science. Skepticism doubts antecedent stoppers to infinite regress like the sensory system, but also the outcome of such filters. Doubting then not only foundational beliefs or what are also called basic beliefs, that do not require epistemic justification as they are traditionally viewed as self-evident, but also reasons that constitute Justified True Belief in some proposition. Some schools of skepticism go so far as to never assent beyond the point of doubt, and therefore never assert anything. Much of epistemology has arisen either in defense of, or in opposition to, various forms of skepticism. Indeed, one could classify various theories of knowledge by their responses to skepticism. For example, rationalists could be viewed as skeptical about the possibility of empirical knowledge while not being skeptical with regard to a priori knowledge and empiricists could be seen as skeptical about the possibility of a priori knowledge but not so with regard to empirical knowledge.

Ancient
Ancient skepticism was considered a way of life, technically more established as such under the Pyrrhonist position but it can be said for the Academics as well. The most notable defenders of ancient skepticism were Arcesilaus of Pitane (315 to 241 BC), Carneades of Cyrene (214 to 129 BC) and Pyrrho of Elis (360 to 270 BC). What is known about Arcesilaus by way of Marcus Tullius Cicero (106 to 43 BC) and Pyrrhonism (a school of skepticism named after Pyrrho of Elis) by way of Sextus Empiricus' (160 to 210 AD) in the Outlines of Pyrrhonism contain very important and influential texts. They symbolize milestones within Greco-Roman philosophy more generally and of ancient skepticism more specifically, actually informing the philosophy of skepticism understood in more modern times.

Pyrrhonian skepticism
Sextus Empiricus wrote about Pyrrhonism within what is called the Origins of Pyrrhonism. The Cambridge Companion to Ancient Scepticism characterizes ancient Pyrrhonism in this way; If that is so, then, given what it is for something to be evident to one, the Sceptic has knowledge of, and so beliefs about, his own pathê. The Sceptic’s pathê include, above all else, his appearances – the states or conditions in which something appears to him to be the case. ... In the opening paragraph of his Outlines of Pyrrhonism, Sextus Empiricus distinguishes three types of philosophers: positive dogmatists who claim to have found the truth; negative dogmatists who declare that the truth cannot be discovered, and those – the Sceptics – who are still searching.

Academic skepticism
A classic philosophical problem within ancient skepticism is the problem of claiming not to assent to anything, yet by making claims around that type of idea the ancient philosophers had to assent to that. To apply skepticism was to be skeptical of skepticism, and so on, actually creating its own self-refutation. Researchers of ancient skepticism, like Michael Frede, try to present an alternative conception model for belief to explain the self-refutation. This position is in opposition to what can be called the standard conception of belief. The standard conception of belief does not see a difference between belief in a proposition and belief that the same proposition is true. The alternative model put forth by Frede is less obvious to the normal person. The need for different conceptions of belief that lack a self-refuting nature are highlighted within the history of Arcesilaus, founder of Academic skepticism. Cicero has characterized Arcesilaus in such ways that the modern skeptic has to put forth alternative conceptions of belief to escape the contradiction inherent in the application of ancient skeptic thought. There has to be good reasons for an alternative conception of belief, yet this is what seems lacking by not only ancient philosophers but contemporary prominent figures attempting to defend skepticism today like Michael Frede or Michael Shermer.

Ancient scepticism, in its most radical forms, calls into question the place of beliefs, or at least beliefs of a certain kind, in the best life. For the Academic scepticism of Arcesilaus consists in part in the claim that one ought not to have any beliefs at all. And Pyrrhonian scepticism, as Sextus Empiricus describes it in his Outlines of Pyrrhonism, is a way of life characterized above all by the absence of beliefs of a certain kind.

Modern
While in today's world skepticism is epistemological, seen to do more damage than good, much less so was this view taken during the time of ancient skepticism. Nowadays, it is rare for philosophers to identify themselves as sceptics; scepticism is typically regarded as a threat to be warded off, not as an outlook to be embraced.

There are still some skeptics in the contemporary setting like Michael Shermer even though the environment for pure skepticism is generally hostile. Michael Shermer is a prominent skeptic and Editor in Chief of the magazine Skeptic. Shermer's skepticism however tacitly recognizes the self-refutation problem of ancient skepticism by formulating his skepticism in light of empiricism and rationalism. Shermer, according to Answers in Genesis, tries to qualify a scientific (empirical) and rational (reasons and logic) basis of his skepticism, attempting to eschew from self-refutation. On one level, the epistemological level, Shermer appeals to ways of knowing being a skeptic of only religious claims. Shermer is then not a philosophical skeptic, in the ancient sense suspending judgement by never making truth claims, but rather he adopts a worldview of atheistic materialism and so is only a religious skeptic. In this regard Shermer can shed the charge of epistemic self-refutation by actually allowing himself to make truth claims with science and logic. Yet on another level, an ontological level that does not deal with knowledge and truth but being and existence and what exists in reality, there lies another contradiction left unanswered by Michael Shermer according to AiG. Since Dr. Shermer seems to be committed to a philosophy of naturalism, how does he account for the existence of reason? Reason involves using laws of logic—which are not part of nature. Laws of logic describe the correct chain of reasoning from premises to conclusions; they are not material and cannot exist in a materialistic universe. The naturalist cannot account for universal, invariant, abstract entities like laws of logic.

Social Skepticism

 * Main Article: Postmodernism

Postmodernism or postmodernity includes poststructuralism within its intellectual landscape of the 20th and 21st centuries. Postmodernism is the move away from modernism of art and architecture, philosophy and truth, and general cultural account and critique. It requires especially the rejection of global cultural narratives, meta-narratives, universal theories, or what are also called grand theories like religious fundamentalism.