(from the Greek, skeptesthai, 'to examine') is the philosophical
view that it is impossible to know anything with absolute certainty,
or to know the world as it 'really' is. The word can also mean a
general reluctance to accept anything on face value without sufficient
proof (as in "He heard that Jim had run the 100m in under ten
seconds but he remained sceptical").
However, Scepticism (with a capital 'S') began in the 5th century
BC in Greece where certain philosophers came to express doubts about
how certain we could be about our knowledge. Protagoras of Abdera
(480-411 BC), for instance, is reported to have said that "man
is the measure of all things" (i.e. that we make the world
in our own image) and Gorgias (485-380 BC) that "nothing exists;
if anything does exist, it cannot be known; if anything exists and
can be known, it cannot be communicated". Many such thinkers
arose from the group known as the Sophists, men who would hire their
skills in debate and argument out to anyone for the right fee. From
this point of view, this form of scepticism is based on the fact
that with enough skill, any argument can sound convincing.
Next came the Pyrrhonists, so called after Pyrrho of Elis, it's
founder, who argued that since we can never know true reality we
should refrain from making judgements. His pupil, Timon of Philius,
followed this by adding that equally good arguments could be made
for either side of any argument (so it was impossible to decide).
The New Academy of the 2nd century BC, founded by Carneades (214-129
BC), taught only that some arguments were more probable than others.
Later sceptics include Aenesidemus (1st century BC), who put forward
ten arguments in support of the sceptical position, and the Greek
physician Sextus Empiricus (3rd century AD), who argued the use
of common sense over abstract theory.
When we reach the Renaissance we can see the influence of Greek
scepticism in such thinkers as the French essayist Michel de Montaigne
(1553-1592), but the sceptical issues only fully resurfaced with
the French philosopher René Descartes ( 1596-1650). Descartes
attempted to use sceptical arguments in order to establish a firm
ground for knowledge. So, Descartes reasoned, if we attempt to subject
everything to doubt we will hopefully discover at some point if
there is anything that cannot be doubted. This he claimed
to achieve in his assertion that it is impossible to doubt that
we are thinking beings - which proves that we exist ( 'Cogito, ergo
sum', which is Latin for 'I think, therefore I am'). By employing
this 'method of doubt', as he called it, Descartes merely used scepticism
as a means to find something certain, and was not therefore actually
The sceptical cause was once again championed by the Scottish empiricist
philosopher David Hume (1711-1776), who argued that certain assumptions
- such as the link between cause and effect, natural laws, the existence
of God and the soul - were far from certain. What little we know
that seems certain, Hume argued, was based on observation and habit
as opposed to any logical or scientific necessity. The German philosopher
Immanuel Kant (1724-1804), influenced by Hume, set limits to human
knowledge by arguing that certain things - such as if there was
proof for God, or if the world had a beginning - did not make sense
to be asked.
The German philosopher Friedrich Nietzsche (1844-1900) argued that
objective knowledge did not actually exist, and his scepticism influenced
in turn that of French Existentialists such as Jean-Paul Sartre
(1905-1980). The American philosopher George Santayana (1863-1952),
argued that all belief - even that in oneself - is irrational (even
though it seems the most natural thing).
Modern day philosophy, although it does not generally take extreme
sceptical arguments very seriously, still retains the influence
of earlier sceptical thinkers.