| Elements of Epistemology |
Classical protagonists of epistemology
Rene
Descartes (1596-1650)
Je Pense, Donc Je Suis The search for knowledge is fraught with difficulties.
Rene Descartes is best known for his unique strategy to conquer some problems
of epistemology. This strategy is, initially, to withhold belief from anything
that is not entirely certain. On close scrutiny, practically everything is open
to doubt. In the process of examining his beliefs, Descartes imagined that a
demon who, while actively trying to deceive him, challenges the belief that the
physical world exists and calls into question the validity of reason. But not
even a demon could deceive someone into believing that he or she does not
exist. Cogito, ergo sum, which is usually translated 'I think, therefore
I am,' is thus beyond skeptical doubt. This is the best part of the Descartes
philosophy. However, entertaining doubt can easily lead to doubts about the
existence of God and at this point Descartes becomes frightened. In 1633, upon
hearing of Galileo barely escaping being burned at the stake, Descartes
destroyed several of his manuscripts and introduced as the basic postulate of
his epistemology an absolute belief in Gods existence as a prerequisite of all
knowledge. Descartes managed to escape persecution. Some, upon hearing this story
contemplated whether the Descartes Cogito, ergo sum should not be better
rendered into English as 'I think, thus I am.'
George Berkeley (1685-1753)
Esse
est Percipi A variation of the ontological
proof of Gods existence was presented by the Bishop George Berkeley, best known
for the main campus of the University of California renamed in 1866 after him,
and for the expression esse est
percipi, (to be is to be perceived).
David Humes (1711-1776)
Will
the Sun Rise Tomorrow? Central to David Humes theory of knowledge is the
classification of knowledge into a priori and a posteriori
categories. A priori knowledge is knowledge attainable prior to experience by
reason alone. A posteriori knowledge is based upon experience. In the course of
deductive reasoning one may attain positive, certain knowledge by building
super-ordinate structures according to the laws of logic from a subordinate set
of a priori truths. A classic example of a super-ordinate structure build by
deduction from a set of postulates is Euclidian geometry. A posteriori
knowledge is derived from experience by induction. While deductive reasoning
seeks positive, certain truth, inductive reasoning makes conclusions that are
only true with some degree of probability. Hume, one of the modern skeptics,
successfully defended the contention that the statement 'the sun will rise
tomorrow' is a statement of probability and not an absolute truth. About a
century after Hume, the procedures of inductive reasoning were formalized by
the theory of inferential statistics.
Immanuel Kant (1724-1804)
Phenomena
and Noumenoa
Immanuel Kant is best remembered for his 'zwei Dinge erfllen das
Gemt mit immer neuer und zunehmender Bewunderung und Ehrfurcht, je fter und
anhaltender sich das Nachdenken damit beschftigt:
der gestirnte Himmel ber mir
und das moralische Gesetz in mir.'
(the starry sky above me and the moral law within me.) Kant claimed that only objects of experience, phenomena, may be known, whereas things lying beyond experience, noumena, are unknowable, and thus in some cases we assume a priori knowledge of them. The existence of such unknowable 'things-in-themselves' cannot be verified by science, yet the belief in God and immortality is mandatory, as morality requires their existence.
