Introductory Remarks
According to A. C. Grayling, “In both the ordinary and philosophical senses, a sceptic is one who, at least unless he is shown satisfactory reason why he should do otherwise, doubts some proposition, belief or theory” (Grayling, 2000:43). This implies that the word ‘scepticism’ connotes ‘doubting,’ ‘questioning,’ and ‘unwillingness to accept a claim without sufficient evidence to back it.’

But etymologically speaking, the term ‘scepticism’ can be traced to the Greek expression skeptikos or skepsis, which means ‘inquirers.’ Simon Blackburn (2005) affirms that although scepticism in ancient Greece focused on the value of inquiry and questioning, nowadays it is usually understood as “the denial that knowledge or even rational belief is possible, either about some specific subject-matter (eg. ethics) or in any area whatsoever” (ibid, 328) There is no doubt that humans are fallible and that the possibility of error in claims to knowledge no matter its source or inspiration can never be completely ruled out.

In classical western philosophy, scepticism emerged from the realisation that the most reliable methods for acquiring knowledge often do not guarantee truth or certainty since, inter alia, appearance is not necessarily identical with reality.

Moreover, these methods sometimes lead to conflicting judgments, with the result that questions of truth become undecidable. From experience, it cannot be denied that what seems to be real and that which is really real are often different. The lacuna between what really is and what appears to be coupled with the fact that reality is in a state of flux led several ancient Greek philosophers such as Heraclitus, Cratylus and Xenophanes to doubt the very possibility of knowing anything. From the time of these thinkers till date, scepticism has been espoused in various degrees by different philosophers such that it is fair to assert that, like every school of thought or perspective in philosophy, each proponent of the sceptical attitude can be described broadly as either moderate or extremist, as the case may be.
II. Evolution of Scepticism in Philosophy
As a systematic critical stance with respect to the knowledge claims, scepticism has remained a constant feature of philosophy right from its evolution in antiquity (Popkin, 1972: 449). As indicated earlier, a number of ancient Greek thinkers had already set the ball of scepticism rolling even before the iconic triumvirate of Greek philosophy – Socrates, Plato, and Aristotle – made their mark in philosophy. Two of them, Gorgias and Protagoras, could be described as extreme sceptics. Gorgias reportedly doubted whether anything exists, and insisted further that if anything existed at all it cannot be known, and that even if it is known it cannot be communicated.

On his part Protagoras, a sophist, claimed that “man is the measure of all things, of the things that are that they are, and of the things that are not that they are not.” Also notable is the brand of scepticism taught by leaders of Plato’s Academy, particularly Arcesilaus and Carneades. Members of this school, having turned their backs on Plato’s metaphysical and mystical teachings, adopted Socrates’ questioning method and focused on working out the implications of the Socratic claim that “All that I know is that I know nothing.”
An interesting influential school of scepticism known as the Pyrrhonian School emerged during the Roman period. The leading ideas of members of this school can be traced to the views of Pyrrho of Elis (c. 365-275B.C.). Taking a principled stance against dogmatism, Pyrrhonism encouraged the refusal to accept the testimony of the senses. A strand of the Pyrrhonian School accepted the phenomena or appearance of things and the customs and moral standards of the society one belongs to, but doubted unnecessary speculations especially about unobservable realities.

In addition, Pyrrhonists argued that since epistemological investigations tend to be frustrating and unproductive because of the difficulty of deciding whether the reasons for accepting any proposition are better or worse than those against it, one should suspend judgement in order to experience ataraxia (or peace of mind). Sextus Empiricus, one of the ablest Pyrrhonians, developed a method of sceptical argumentation that leads to epoché (suspension of judgement) about issues concerning what is not evident.During the Middle Ages, St. Augustine’s Contra Academicos, which was an attempt to respond to the scepticism of the Academicians, represented the Christian discourse on scepticism. Al-Ghazali and Yehuda Halevi, Muslim and Jewish theologian respectively, not only criticised Aristotelians of the medieval period but also questioned the very possibility of rational scientific and theological knowledge about the real nature of the cosmos. But unlike their ancient Greek counterparts who were primarily motivated by the desire to delineate the cartography of certain indubitable knowledge, if at all that is possible, Arabic and Jewish sceptics were more interested in projecting a mystical and non-rational engagement with religious truths by displaying the intellectual poverty of the so-called rational theologies prevalent at that time (ibid, 451). Yet the mystical non-rational perspective suffers from a worse defect than the rational theologies al-Ghazali and others criticised because of its extreme subjectivity and decoupling from reason and empirical evidence.At the beginning of the renaissance period, the Academic sceptics and their Pyrrhonian counterparts focused mainly on theological controversies. For instance Erasmus, in his work, in Praise of Folly, ridiculed some scholastics for their endless, epistemologically barren, theological disputations. In De Libero Arbitrio he criticized Martin Luther and pointed out that the problem of free will was too complicated for humans to comprehend and that scriptural interpretations cannot resolve the problem. Michel de Montaigne, the patron-saint of scepticism in sixteenth century France, set the stage for the problems of modern philosophy.
Montaigne underscored the difficulties of judging the reliability of sense perception, adding that idiosyncratic, social, and cultural factors play an important part in the manner people interpret reality. He even argued that the criteria used in determining standards of judgement themselves are open to doubt “unless God gives us some indubitable first principles and makes our faculties reliable” (ibid, 452). The writings of sceptics like Erasmus, Sextus Empiricus, Montaigne, and Pierre Gissendi provided the background for René Descartes’ version of scepticism. Descartes claimed that by deploying the methodic doubt more rigorously than sceptics before him had, one can discover indubitable standard for true knowledge which leads to rationally interlocking truths about reality. In other words, the Cartesian approach begins with scepticism, applies it to discover the foundation of certain knowledge (cogito ego sum), and then stretches it further to distil indubitable metaphysical knowledge from clear and distinct ideas. However, critics correctly doubted whether the cogito proved anything at all, and whether it could serve as a solid foundation for knowledge. As Gassendi, one of Descartes’ contemporaries observed, what Descartes thought to be indubitable truths might actually be a subjective worldview in his mind and not a true representation of reality.
The major works of David Hume and Immanuel Kant contain significant sceptical conclusions. In A Treatise of Human Nature and Enquiry Concerning Human Understanding, Hume maintained that no truths about matters of fact could be proved deductively or inductively. Moreover, the notions of “uniformity of nature” and “necessary connection” that underpin induction cannot be established since the evidential value for them are inconclusive. In the last chapter of the Enquiry and Dialogues Concerning Natural Religion, Hume raised doubts regarding the trustworthiness of rational and empirical reasoning in philosophy and theology, and questioned the reasons philosophers had advanced for belief in the existence of an external world, the self, and God. It is interesting to note that Hume recognised that his extreme scepticism is unsuitable for practical living, which is an indirect acknowledgement that scepticism taken too far is unsustainable.
On his part Kant, having assumed that scientific knowledge is possible, tried really hard to respond to the skeptical conclusions of Hume as regards the very possibility of knowing reality. The result was his magnum opus, Critique of Pure Reason. The key problem, for Kant, is to provide a convincing account specifying the conditions for all possible experience. He believed that he had met Hume’s sceptical challenge with his own version of the Copernican revolution. Kant held that knowledge begins with experience, but does not arise from it. He maintained that the categories of human understanding (including causality, space and time), and the logical forms of judgement are the conditions for all knowledge about the phenomenal world, that is, the world as it appears to us as human beings.
Nevertheless, the categories and logical forms are not applicable to the noumenal world, the world of things-in-themselves, which comprises the actual contents of experience, the self and God. The fundamental limitations of Kant’s analysis of knowledge were not lost on other philosophers shortly after his critical philosophy was published. For example, G. E. Schultze insisted that Kant did not resolve Hume’s skepticism which woke him (Kant) from dogmatic slumbers because of his failure to go beyond the subjective preconditions for the possibility of experience to any objective or subject-independent# claims about reality. Another critic, Salomon Maimon, agreed with Kant on the reality of the a priori categories or concepts necessary for knowledge, but insisted that their applicability to experience depends on inductions from experience whose validation is purely a matter of probability, not certainty.
Interestingly, a theologian, Johann Georg Hamann, used the sceptical arguments of Hume and Kant to launch his antirational fideism, the doctrine that knowledge depends on faith rather than reason. Now, two notable German metaphysicians, Johann Fichte and G. W. F. Hegel tried to avoid the sceptical submissions of Hume and Kant through a shift in focus towards creativity and the historicity of knowledge. For both philosophers, scepticism is a stage in the understanding of unfolding events that could be overcome by the creative construction of, and commitment to, an all-embracing worldview.
Furthermore, although Hegel values scepticism as a movement that respects the freedom of reason, the racist, sweeping, magisterial tone of some of his views tend to promote intellectual hubris, not scepticism. It was not too long before the speculative metaphysics of German idealists like Hegel and its incarnation in Britain by F. H. Bradley was subjected to critical fire by Bertrand Russell, G. E. Moore and the logical positivists. The Russellian and positivist critiques included a strong anti-metaphysical component in the form of scepticism about, or outright rejection of, transcendental metaphysical knowledge. Russell, like the positivists, put premium on knowledge derived from logic, mathematics and science. Nevertheless, because scientific knowledge is probabilistic, he rejected dogmatic claims to knowledge by metaphysicians and theologians. The logical positivists and linguistic philosophers (in particular) ushered in what is often described as the linguistic turn in philosophy. Deploying different strategies, these philosophers attempted to circumvent the perennial problems of scepticism by positing that knowledge properly so-called is restricted to logically true propositions, empirically verifiable facts, and commonsense assertions and beliefs. The positivist move from hardnosed idealism to science, mathematics and commonsense seems reasonable. Yet, as critics such as Karl Popper have observed, the positivist verifiability principle cannot serve the dual purpose for which it was formulated in the first instance, whereas the quest for indubitable empirical foundation for science or knowledge generally cannot be fulfilled. Linguistic philosophers have been accused of deviating from the interesting problems that oxygenate philosophy through “excessive concern with the contours of everyday linguistic usage characteristic of some philosophers at Oxford in the years following the Second World War” (Blackburn, 212).

Popper himself can be justly described as a moderate sceptic. He insisted that although the aim of science is truth, there is no guarantee that any scientific hypothesis can be shown to be true due to the ever present possibility of falsification. Aside from that Popper, unlike the foundationists, rejected the notion that science can be grounded on a solid epistemological foundation. He emphasised the dynamic, fallible and progressive character of knowledge. Popper’s thoroughgoing rejection of induction has been shown to be unsuccessful on the ground that his advice that scientists should work with the best corroborated hypothesis is inductive in nature.In contemporary times, disillusionment with the idea of the inevitability of progress and the collapse of hopes for peace, justice and happiness across the world (which are some of the far-reaching outcomes of the two world wars), increasing global socio-economic challenges and political upheavals, not to talk of the worsening climate disruptions and threat of nuclear war, have compelled many intellectuals to express serious scepticism about humanity’s capacity to really comprehend the world, and about the significance and value of the ideals that have guided humans since they evolved as a distinct species. The growing uncertainties of the present have led to the questioning of received basic assumptions hitherto taken for granted and deepened disenchantment with settled traditional world outlooks derived from religion and culture. Nowadays, the quest is on for more satisfactory bases of certainty, knowledge and values that also accommodate the incredible global changes and innovations that spring from science and technology. Presently, we live in a world of incredible opportunities within the penumbra of tantalising uncertainties, with the current developments in Artificial Intelligence (AI) adding a new dimension to the precariousness of the future.
The Value of Scepticism
The brief historical sketch of scepticism presented above provides a useful context for a better comprehension of the broad contours of scepticism over time. Obviously, the Enlightenment period which opened the door to the scientific and cultural progress in Europe and her cultural colonies in North America in subsequent centuries is one of the most important fruits of scepticism. As we have seen from the preceding discussion, while some philosophers have questioned the possibility of actually knowing anything at all, others have raised doubts regarding the epistemic credentials of specific knowledge-claims and methodologies. Now, imagine that at one extreme there is complete credulity and at the other total scepticism, one can rank individual’s attitude towards knowledge-claims or beliefs systems between these two extremes. Willingness to belief any proposition without regard to evidence is definitely inimical to productive and fulfilling existence, whilst the extreme sceptical claim that noting is, or can be, known is self-defeating and should be ignored because if true then we do not know or cannot know that we know nothing. A more rewarding way of looking at scepticism is to see it as a challenge or interrogation of -claims made in a particular discipline or area of human activity, which in turn depends on the form and nature of the discipline or activity under consideration. The implication here is that generally speaking to be a sceptic is to request for the reason(s), justification or basis for accepting a particular assertion or belief as true. More often than not, such a request is motivated by the suspicion that the reason or justification might be unsatisfactory or inadequate. Although scepticism in philosophy, particularly those variants of it that lean too closely to the extreme, has been criticised for good reasons, a healthy dose of the sceptical attitude is important both in every serious intellectual pursuit and in everyday living. In philosophy, scepticism has functioned as an intellectual gadfly against dogmatic philosophical theories and systems presented as if they are eternal verities beyond the penetrating searchlight of rational inquiry, thereby encouraging philosophers to be intellectually honest in their postulations, and helping to clarify the infrastructure of claims to knowledge. As a result, scepticism has contributed a lot to intellectual progress by triggering continuous re-examination of philosophical ideas and theories leading to new doctrines which try to avoid the errors or difficulties of previous ones. It has spawned new perspectives on different topics and novel ingenious criticisms, including penetrating criticisms of criticisms. Were it not for sceptics, it would have been a herculean task to separate beliefs backed by sufficient evidence from opinions based on prejudice, superstition or popular enthusiasm. Of course, the progressive sanitising effects of the questioning attitude in philosophy have also been replicated with impressive outcomes in other fields of intellectual endeavour. Surely, given that intellectual reflection is the natural endowment of human beings as such irrespective of race and culture, it is reasonable to infer that philosophers in other parts of the world such as Africa, Asia, and the Americas, like their counterparts in Europe, questioned the received belief systems of their cultures given that no worldview or opinion on the perennial problems that ignite philosophical reflection is error-proof. Aristotle was correct when he affirmed that it was through wonder that humans began to philosophise. To wonder about the mysteries of the universe entails scepticism, and anywhere there is tolerance of scepticism the probability of progress is higher than where dogmatism predominates given that whatever answers to the perennial questions of philosophy offered at any point in time can always be revised whenever new relevant evidence that challenges them becomes available.For the average human being and the society generally, what is the value of scepticism, the attitude of doubting, of suspending judgement when evidence is inadequate? The short answer is – scepticism is invaluable for both since it is virtually impossible to overestimate the value of the sceptical attitude. This can be illustrated by focusing attention on two domains in which the sceptical attitude is of utmost importance, namely, politics and religion. In politics, or more precisely, the system for authoritative allocation of power, resources, and responsibilities to members of a society, supporters of western multi-party democracy and autocracy or totalitarianism (as practised in China and Russia) tend to accept uncritically certain claims about the superiority of one over the other. It is clear that each of these political arrangements (and its cognate economic system) has both advantages and disadvantages. But those in favour of each system often ignore this and cling dogmatically to the one they prefer usually without sufficient evidence or justification. In this connection, the repressive character of authoritarianism makes it unacceptable to those who cherish individual freedom and protection of basic human rights. But although there are reasonable grounds for preferring liberal democracy to authoritarianism, there are good reasons to be sceptical about the suitability of such arrangement especially for African countries where modern democratic institutions, traditions, and culture are yet to emerge and take root. A good example is Nigeria, where those running the system have performed far below expectation. Perhaps, as the late literary icon Prof. Chinua Achebe noted in his little book, The Trouble with Nigeria, the problem is more of poor leadership, not with the system of democratic governance as such. That said, Nigerians need to adopt the sceptical attitude towards their leaders and be prepared to interrogate every aspect of the political process. In addition, they should not accept lock, stock and barrel the sugar-coated promises of politicians especially during campaigns since experience has shown that once they get into office their primary objective is to satisfy their bulimic quest for primitive accumulation. Effective democratic praxis requires a certain level of enlightenment amongst the people on the need to hold political office holders accountable through creative mobilisation of their collective will. Non-violent protests and civil disobedience, for example, are recognised globally as acceptable means of bringing about improved governance and positive change in the society. If there is any aspect of human activity where scepticism is needed, and urgently too, it is in religion or faith, since that is the only domain where dogmatism and willingness to believe even when sufficient evidence is unavailable or grossly inadequate is considered a praiseworthy virtue, an act of piety. The Bible, in Hebrews 11-1, defines faith as “the assurance of things hoped for, the conviction of things not seen.” Therefore, faith is the very antithesis of the sceptical attitude. The number of bizarre claims in the so-called Holy Scriptures, in addition to the messages preached in churches, mosques and other religious centres that contradict common sense and well-established laws of science is staggering. In Nigeria and other African countries, religion has stifled the capacity for critical thinking and the questioning attitude in the general population, including the educated elite, leading to the mass production of gullible superstitious individuals in all strata of the society. In the universities, the expanding eddies of religious dogma across board is very alarming and detrimental to the emergence of enlightened citizens with appropriate scientific outlook necessary for civilised behaviour and progress both at the personal and social levels. All manner of charlatans, fraudsters, and preachers of highfalutin nonsense masquerading as “men and women of God” continue to exploit the fears, insecurities, and gullibility of the people just because right from childhood most of them had been brainwashed to believe without question the contents of The Bible, The Koran, and their ordained interpreters. As a corollary, religion is the only subject where doubt or challenging what is written in holy books is seen as a taboo or sacrilege that must be discouraged. A significant number of people have unwittingly destroyed, sometimes irreparably, their occupations, personal relationships, and health due to unquestioning adherence to religious dogma.
The case of late Prof. Dora Akunyili, the globally celebrated former Director General of NAFDAC, is a tragic example of the horrible consequences of lack of healthy dose of scepticism, of believing sheepishly in purported supernatural intervention in human affairs even in situations where effective manmade solutions are available.
Concluding Remarks
From the foregoing, it can be inferred that scepticism is a significant motivating factor, perhaps the centre of gravity, not just in serious philosophising but also for deep reflection about any aspect of reality and human existence in their incredibly diverse manifestations. Certainly, throughout history blind faith and dogmatism have done unspeakable harm to human civilisation. Dogmatic belief in heaven and hellfire, the idea that a certain deity, prophet, political ideology or religious doctrine is worth dying for, outrageous antediluvian blasphemy laws in Muslim majority countries, jungle justice leading to extrajudicial murders, cruel maltreatment and killing of children and adults accused of witchery, bloody conflicts in various parts of the world fuelled by ancient hatred – indeed a vast majority of the evils human beings commit against one another – originated from the unquestioning acceptance of some unsubstantiated doctrine or superstition. These evils would go down considerably if the attitude of scepticism, of suspending judgement when evidence is either unavailable or inconclusive, is widespread in a vast majority of the human population. In my view, if humanity is to eliminate or reduce to the barest minimum many of the manmade evils destroying the world today, particularly religious superstitions and belief systems that encourage corrosive egoism, hubris, discrimination, mutual distrust, jealousy, hatred, and war everyone must be encouraged to cultivate the sceptical or critical attitude. Specifically, right from the home children should be taught not to accept any proposition as true unless there is good evidence for it. At various levels of education teachers should reinforce this attitude by teaching their pupils and students the intellectual and practical advantages of asking probing questions, of forming opinions based on adequate evidence, and of changing their minds when superior evidence conflicts with their cherished beliefs. It is important to stress that that nothing under the sun is beyond the whetstone of criticism. If the habit of scepticism and questioning accepted beliefs becomes dominant worldwide, the benefits to humanity will be incalculable. In this regard, it is recommended that everyone should endeavour to imbibe the philosophical temperament or what Bertrand Russell referred to as “the habit of exact and careful thought,” more so in matters that have serious practical consequences for individuals and the society as a whole.
The major lesson to be distilled from this discourse be encapsulated in the following words, “If you are not sure of the truth of any proposition or claim, do not act as if you are certain.” Another way of stating it is “Before acting on any belief that could have harmful consequences for yourself or others, consider the possibility that you might be mistaken.” A healthy dose of scepticism is an indispensable antidote to the venom of blind faith, superstition and dogmatism.
References
Blackburn, S. (2005). Oxford Dictionary of Philosophy, Oxford: Oxford University Press.Grayling, A. C. (2000). “Skepticism,” Philosophy 1, Oxford: Oxford University Press.Russell, B. () Unpopular Essays, London: Unwin Paperbacks.Popkin, R.H. (1972). “Skepticism,” Encyclopedia of Philosophy, Paul Edwards (ed), New York & London: Macmillan.