Sextus Empiricus is the most eminent physician and philosopher of the Skeptical School of Philosophy, which was closely connected with the Empirical Medical School in the Hellenistic Era.¹ Sextus, as physician, was also associated with the Methodical School of Medicine, believing that Methodism is most worthy of the skeptic.² Reasonably, many of his opinions and doctrines in Medicine obviously agree with the principles of the Empirical and Methodical Schools and are entirely against the principles of Dogmatics.^2,3 However Sextus was mostly known in the literature as a skeptic thinker rather than as empirical or methodic physician.⁴

Sextus wrote and taught mostly in Hellenistic Alexandria,⁵ the seat of Pyrrhonian skepticism, at the latter part of the second century AD. His works are “Pyrrhonean Hypotyposes” (Outlines of Pyrrhonism) in three volumes and “To mathematicians” (Adversus Mathematikus) in eleven volumes, which are meticulous summing up of the wisdom of the Skepticism.⁶ Sextus wrote three more books two on Medicine, entitled Medical memories and Empirical memories and another on Soul, which are unfortunately lost during the centuries The style of Sextus’ writings is fluent, concrete and precise, reminding mostly Plutarch.

On Skepticism Sextus asserts that it is a movement (αγωγή) for finding the truth.⁷ The term “sceptic” is a derivative of the noun, skepsis (σκέψις), which means thought, examination, inquiry, consideration, meditation, investigation, problematizing and analytical thinking.

The term Skepticism or Skeptics was mainly applied to members of Plato’s Academy during its late period. Skepticism, as a Post-Classical, Hellenistic philosophical movement, is based on the evaluation of phenomena, which constitute the appearance of objects, the guidance of nature and the impulse of human feelings.⁸ The right and careful analysis of the phenomena might provide a straight and practical way of life, leading to interior peace and mental tranquility, inducing “ataraxia”, which is an ideal state of psychological equilibrium and a safe escape from interior contradictions, controversies and unbalance, resulting in the establishment of the inner harmony eventually.⁹

The skeptical way of life of a philosopher was characterized by persistent commitment to investigate the truth, based on objective arguments and real evidence, avoiding any dogmatic insistence and tendency of mind.¹⁰ As a matter of fact, the phenomena are quite relative and changeable, so that a definite and certain knowledge could not be crystallized upon them. Moreover, the subjective state of thinking of every human being may modify the character of the real perception and mental representation of each phenomenon.¹¹ Thus, Sextus insisted reasonably that for every reasoning might be an equally strong opposite reasoning.¹² Therefore the reality of things seems to be inaccessible and definite certitude would be impossible for the reasoning.

All arguments and hypothesis could be opposed by other strong arguments of the same persuasive force and validity, based on the dynamics of the philosophical investigation and dialectics. For historical reasons we would say that Philosopher Arcesilaus was the first to argue on both sides of a question. Sextus emphasizing insists that the skepticism does not accept or reject any impression and substantially does not affirm or deny anything concept or theory.¹ Logic is based on phenomena and criteria. By the continuous investigation the thinker or the scientist is prevented from mental or psychological inactivity (ανενεργησία). The only wise way of life is to suspend judgment, regarding everything, never facing the risk of being wrong in anything consequently.

Sextus proposed several practical criteria and ten main ways (modes, τρόποι) that the man could follow whenever he would decide to suspend judgment on absolute truth.¹³ The main mode is the “epoché” (εποχή) or suspension of judgment, in order to achieve the deep interior peace and serenity of mind, since the psychological equilibrium or imperturbability (αταραξία) must be the supreme target of the human life, leading to permanent well-being (ευδαιμονία),¹⁴ in an attempt to be raised above the discomfort of the suffering of the soul, which is imposed by psychological distress and inner disharmony.¹⁵ However, the peace of mind and the imperturbability (ataraxia) have only an exterior and provisional character, protecting the soul from anxiety and fear, without being able to fulfill the human expectations for existential harmony and truthful life, which is offered by the genuine, constant, unalterable eternal values.

Sextus considered that science is the main source of pure knowledge, underling at the same time the relativity of the scientific data. Science, therefore, could not provide the authoritative truth and all its issues must be understood from a dialectical perspective, since whatever is debatable may concern reality. The scientific methodology consists of investigation, as starting point, of equipollence, an objective estimation and evaluation of all positive and negative aspects, of suspension of judgment and of tranquility of mind and imperturbability.¹⁶ Every effort to approach the truth is feasible only by assessing the phenomena objectively, since absolute reality could never be known. Always the reality has to be investigated but the appearance, the phenomenon must be accepted without any debate, since it is clearly obvious.¹⁷

According to skepticism the real nature of things, the real existence or hypostasis of everything is unclear. For approaching the reality the philosopher and the scientist must avoid dogmatism, subjectivity, empathy and the tendency to believe in his own opinion and remain fixed on it. It is very important for the scientist to work in a state of having no opinion (a condition called ἐποχὴ) and to investigate anything and arguing anything in peace, in mental serenity (ἀταραξία), suspending any judgment, contradictions and futile competitions. Sextus offers a psychotherapeutic regime, for the liberation of the scientist from the ambition of the domination and preponderance and from the passion of arrogance and authority, suggesting that the best way for retaining the interior clarity, the peace, the tranquility, the serenity, the self-respect and the pure scientific creativity is the suspension of judgment, beyond the futile competition and dogmatism.¹⁸

The human mind has the innate capacity for perception, thinking, analysis of the phenomena, ability to distinguish what is true and what is false and to meditate avoiding dogmatism. Sextus insists that any argument requires definite proof, precisely proven. In addition, it is reasonable that not everything conceived has always a share in the real existence.¹⁹ Therefore, the liberation of the epistemological thinking from dogmatic fixations or from immense and chaotic speculations and the orientation exclusively towards research and scientific investigation, may induce a remarkable pragmatism, arguing that there are objective ways of approaching the scientific truth. Thus, scientific skepticism has to criticize any veracity of assertions, which are not based on empirical evidence or verified experimental data .²⁰

Moreover, the continuous dispute and the lack of a definite decision and of a stable scientific cataphatism may relieve the scientist and the thinker from the burden and the worry of an eventual false option and of the consequent criticism.²¹ The high fever of the intensive scientific research in the last years may be enforced by the anxiety for a beneficial contribution to the quality of the human life and the genuine enthusiasm for approaching the pure scientific reality. However, the scientific achievements open the horizons of the scientist even further showing that the real knowledge is not easily accessible, without being also totally inaccessible.²²

In the field of neurosciences, the recent achievements of the ongoing research, concerning the knowledge of the multi-dimensional potentiality and capacity of the human brain, the amazing synaptic activity and the miraculous neuronal plasticity as well as the numerous roots of the psychosomatic interactions, verify the crucial concept of the skepticism, that the acceptance of any scientific theory and principle requires a ‘critical and repeated experimental verification’, providing strong evidence that the theory is based on objective data.²³ In addition, the scientist in order to suspend judgment on the validity of opposed theories needs to proceed to an accurate and critical experimentation for revealing the validity of the right theory, based on concrete evidence.

Many modern scientific theories are the fruits of Sextus’ skepticism.²⁴ Sextus’ main theory of relativity,²⁵ which was revitalized and experimentally proved, many centuries later, by physics and mathematics, was the supreme concept, which opened new immense horizons in physics, biological science, in the evidence based Medicine, in neurosciences and neurophilosophy.

Sextus’ skepticism exerted also a strong influence on and the current Psychology and Psychopathology.^26,27 Jaspers described the “skeptic” personality, which is characterized by uncertainty, criticism, debate and dispute without any conclusion.²⁸

We would say that according to Sextus the skeptic personality of a Neuroscientist would be characterized by the serenity of mind, the fever for research and non-ceased investigation, endeavoring to approach the truth without empathy, in a tranquil objectivity and peaceful criticism, avoiding personal ambition, stereotyped behavior and dogmatism.

None.

Author declares no conflicts of interest.

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