|
Branches of Philosophy
(VII)
Spinoza’s solution to the mind-body problem explained the apparent
interaction of mind and body by regarding them as two forms of the same
substance, which exactly parallel each other, thus seeming to affect each
other but not really doing so. Spinoza’s ethics, like the ethics of Hobbes,
was based on a materialistic psychology according to which individuals are
motivated only by self-interest. But in contrast to Hobbes, Spinoza
concluded that rational self-interest coincides with the interest of others.
Locke
English philosopher John Locke responded to the challenge of Cartesian
dualism by supporting a commonsense view that the corporeal (bodily or
material) and the spiritual are simply two parts of nature that remain
always present in human experience. He made no attempt to rigorously define
these parts of nature or to construct a detailed system of metaphysics that
attempted to explain them; Locke believed that such philosophical aims were
impossible to carry out and thus pointless. Against the rationalism of
Descartes and Spinoza, who believed in the ability to achieve knowledge
through reasoning and logical deduction, Locke continued the empiricist
tradition begun by Bacon and embraced by Hobbes. The empiricists believed
that knowledge came from observation and sense perceptions rather than from
reason alone.
In 1690 Locke gave empiricism a systematic framework with the publication of
his Essay Concerning Human Understanding. Of particular importance was
Locke’s redirection of philosophy away from the study of the physical world
and toward the study of the human mind. In so doing he made epistemology,
the study of the nature of knowledge, the principal concern of philosophy in
the 17th and 18th centuries. In his own theory of the mind Locke attempted
to reduce all ideas to simple elements of experience, but he distinguished
sensation and reflection as sources of experience, sensation providing the
material for knowledge of the external world, and reflection the material
for knowledge of the mind.
Locke greatly influenced the skepticism of later British thinkers, such as
George Berkeley and David Hume, by recognizing the vagueness of the concepts
of metaphysics and by pointing out that inferences about the world outside
the mind cannot be proved with certainty. His ethical and political writings
had an equally great influence on subsequent thought. During the late 18th
century the founders of the modern school of utilitarianism, which makes
happiness for the largest possible number of people the standard of right
and wrong, drew heavily on the writings of Locke. His defense of
constitutional government, religious tolerance, and natural human rights
influenced the development of liberal thought during the late 18th century
in France and the United States as well as in Great Britain.
Idealism and Skepticism
Efforts to resolve the dualism of mind and matter, a problem first raised by
Descartes, continued to engage philosophers during the 17th and 18th
centuries. The division between science and religious belief also occupied
them. There, the aim was to preserve the essentials of faith in God while at
the same time defending the right to think freely. One view called Deism saw
God as the cause of the great mechanism of the world, a view more in harmony
with science than with traditional religion. Natural science at this time
was striding ahead, relying on sense perception as well as reason, and
thereby discovering the universal laws of nature and physics. Such empirical
(observation-based) knowledge appeared to be more certain and valuable than
philosophical knowledge based upon reason alone.
After Locke philosophers became more skeptical about achieving knowledge
that they could be certain was true. Some thinkers who despaired of finding
a resolution to dualism embraced skepticism, the doctrine that true
knowledge, other than what we experience through the senses, is impossible.
Others turned to increasingly radical theories of being and knowledge. Among
them was German philosopher Immanuel Kant, probably the most influential of
all because he set Western philosophy on a new path that it still follows
today. Kant’s view that knowledge of the world is dependent upon certain
innate categories or ideas in the human mind is known as idealism.
Leibniz
German philosopher Gottfried Wilhelm Leibniz, like Spinoza before him,
worked in the rationalist (reason-based) tradition to produce a brilliant
solution to the problems raised by dualism. Leibniz, a mathematician and
statesman as well as a philosopher, developed a remarkably subtle and
original system of philosophy that combined the mathematical and physical
discoveries of his time with the organic and religious conceptions of nature
found in ancient and medieval thought. Leibniz viewed the world as an
infinite number of infinitely small units of force, called monads, each of
which is a closed world but mirrors all the other monads through its
activity, which is perception. All the monads are spiritual entities, but
they can combine to form material bodies. Leibniz conceived of God as the
Monad of Monads, which creates all other monads and predestines their
development.
Leibniz’s theory of the predestination of monads, also called the theory of
preestablished harmony, entailed a radical rejection of causality—the view
that every effect must have a cause. According to Leibniz, monads do not
interact with each other at all, and the appearance of mechanical causality
in the natural world is unreal, akin to an illusion. Likewise, there is no
room in the universe for free will: Even though we enjoy the illusion of
acting freely, all human actions are predetermined by God. Despite these
gloomy conclusions, Leibniz’s philosophy was profoundly optimistic because
he argued that ours was the best of all possible worlds. He based this
belief on considerations about the nature of truth and necessity. French
writer Voltaire mocked this viewpoint in Candide (1759), a satirical novel
that examines the woes heaped on the world in the name of God.
Berkeley
In the 18th century Irish philosopher and Anglican churchman George
Berkeley, like Spinoza before him, rejected both Cartesian dualism and the
assertion by Hobbes that only matter is real. Berkeley maintained that
spirit is substance, and that only spiritual substance is real. Extending
Locke’s doubts about knowledge of an external world, outside the mind,
Berkeley argued that no evidence exists for the existence of such a world,
because the only things that we can observe are our own sensations, and
these are in the mind. The very notion of matter, he maintained, is
incoherent and impossible. To exist, he claimed, means to be perceived (“esse
est percipi”), and in order for things to exist when we are not observing
them, they must continue to be perceived by God. By claiming that sensory
phenomena are the only objects of human knowledge, Berkeley established the
view known as phenomenalism, a theory of perception that suggests that
matter can be analyzed in terms of sensations.
Hume
Whereas Berkeley argued against materialism by denying the existence of
matter, 18th-century Scottish philosopher David Hume questioned the
existence of the mind itself. Hume’s skeptical philosophy also cast doubt on
the idea of cause as understood in all previous philosophies and seriously
disputed earlier arguments for the existence of God. His most important
philosophical work, A Treatise of Human Nature, was published in three
volumes in 1739 and 1740.
All metaphysical assertions about things that cannot be directly perceived
are equally meaningless, Hume claimed, and should be “committed to the
flames.” In his analyses of causality and induction, Hume revealed that
there is no logical justification for believing that any two events which
occur together are connected by cause and effect or for making any inference
from past to future. Hume noted that we depend on our past experience
whenever we form beliefs about anything that we do not directly perceive and
whenever we make predictions about the future. According to the empiricist
doctrine of Bacon, Locke, and Berkeley, we can do this because experience
teaches us what particular things belong together as causes and effects.
Hume, however, argued that this attempt to learn from experience is not at
all rational, thus calling into question the reliability of our memories,
our reasoning processes, and our ability to learn from past experiences or
to make even the smallest predictions about the future—for example, that the
sun will rise tomorrow. Though extreme, Hume’s skepticism about
philosophical empiricism raised problems about the possibility of knowledge
that contemporary philosophers still struggle to resolve.
Kant
German philosopher Immanuel Kant was among the first to appreciate Hume’s
skepticism, and in response he published the Critique of Pure Reason (1781),
widely considered the greatest single work in modern philosophy. In this
work Kant made a thorough and systematic analysis of the conditions for
knowledge. As an example of genuine knowledge, he had in mind the
contributions to physics of English scientist Isaac Newton. In the case of
Newtonian physics, reason seemed to have done an effective job of
understanding the data supplied by the senses and to have succeeded in
postulating universal and necessary laws of nature, such as the law of
gravitation and the laws of motion. Kant proposed to explain how such
knowledge is possible, thereby providing a complete reply to Hume’s
skepticism and answering many of the problems that had plagued Western
philosophers since the time of Descartes.
|
SITE TOOLS |
|
Print This Page
SATURDAY, NOVEMBER 4 2006