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3 MODERN SCHOOLS
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Rationalism is the philosophical view
that regards reason as the chief source and test
of knowledge. Holding that reality itself has an
inherently logical structure, the Rationalist
asserts that a class of truths exists that the
intellect can grasp directly. There are, according to the Rationalists, certain
rational principles--especially in logic and mathematics, and even in ethics
and metaphysics--that are so fundamental that to
deny them is to fall into contradiction. The Rationalist's confidence in reason
and proof tends, therefore, to detract from his respect for other ways of
knowing. Rationalism has long been the rival of Empiricism,
the doctrine that all knowledge comes from, and must be tested by, sense
experience. As against this doctrine, Rationalism holds reason to be a faculty
that can lay hold of truths beyond the reach of sense perception, both in
certainty and generality. In stressing the existence of a "natural
light," Rationalism has also been the rival of systems claiming esoteric
knowledge, whether from mystical experience, revelation, or intuition, and has
been opposed to various irrationalisms that tend to stress the biological, the
emotional or volitional, the unconscious, or the existential at the expense of
the rational. (see also epistemology,
mathematics, philosophy of) |
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Rationalism has somewhat different
meanings in different fields, depending upon the kind of theory to which it is
opposed. |
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In the psychology
of perception, for example, Rationalism is in a
sense opposed to the genetic psychology of the Swiss scholar Jean Piaget, who,
exploring the development of thought and behaviour in the infant, argued that
the categories of the mind develop only through the infant's experience in
concourse with the world. Similarly, Rationalism is opposed to Transactionalism,
a point of view in psychology according to which man's perceptual skills are
achievements, accomplished through actions performed in response to an active
environment. On this view, the experimental claim is made that perception is
conditioned by probability judgments formed on the basis of earlier actions
performed in similar situations. As a corrective to these sweeping claims, the
Rationalist defends a nativism, which holds that certain perceptual and
conceptual capacities are innate--as suggested in the case of depth perception
by experiments with "the visual cliff,"
which, though platformed over with firm glass, the infant perceives as
hazardous--though these native capacities may, at times, lie dormant until the
appropriate conditions for their emergence arise. (see also innate
idea) |
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In the comparative study of languages, a
similar nativism was developed in the 1950s by the innovating syntactician Noam
Chomsky, who, acknowledging a debt to Descartes,
explicitly accepted the rationalistic doctrine of "innate ideas."
Though the 4,000 languages spoken in the world differ greatly in sounds and
symbols, they sufficiently resemble each other in syntax
to suggest that there is "a schema of universal grammar" determined by
"deep structures" or "innate presettings" in the human mind
itself. These presettings, which have their basis in the brain, set the pattern
for all experience, fix the rules for the formation of meaningful sentences, and
explain why languages are readily translatable into one another. It should be
added that what Rationalists have held about innate ideas is not that some ideas
are full-fledged at birth but only that the grasp of certain connections and
self-evident principles, when it comes, is due to inborn powers of insight
rather than to learning by experience. (see also linguistics) |
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Common to all forms of speculative
Rationalism is the belief that the world is a rationally ordered whole, the
parts of which are linked by logical necessity and the structure of which is
therefore intelligible. Thus in metaphysics it is opposed to the view that
reality is a disjointed aggregate of incoherent bits and is thus opaque to
reason. In particular, it is opposed to the logical
atomisms of such thinkers as David Hume
and Ludwig Wittgenstein, who held that facts are
so disconnected that any fact might well have been different from what it is
without entailing a change in any other fact. Rationalists have differed,
however, with regard to the closeness and completeness with which the facts are
bound together. At the lowest level, they have all believed that the law of contradiction
"A and not-A cannot coexist" holds for the real world, which means
that every truth is consistent with every other; at the highest level, they have
held that all facts go beyond consistency to a positive coherence; i.e.,
they are so bound up with each other that none could be different without
all being different. |
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In the field where its claims are
clearest--in epistemology, or theory of knowledge--Rationalism holds that some,
at least, of man's knowledge is gained through a priori (prior to experience),
or rational, insight as distinct from sense experience, which too often provides
a confused and merely tentative approach. In the debate between Empiricism and
Rationalism, Empiricists hold the simpler and more sweeping position, the Humean
claim that all knowledge of fact stems from perception. Rationalists, on the
contrary, urge that some, though not all, knowledge arises through direct
apprehension by the intellect. What the intellectual faculty apprehends is
objects that transcend sense experience-- universals and their relations. A universal is an abstraction, a
characteristic that may reappear in various instances: the number three, for
example, or the triangularity that all triangles have in common. Though these
cannot be seen, heard, or felt, Rationalists point out that man can plainly
think about them and about their relations. This kind of knowledge, which
includes the whole of logic and mathematics as well as fragmentary insights in
many other fields, is, in the Rationalist view, the most important and certain
knowledge that the mind can achieve. Such a priori
knowledge is both necessary (i.e., it
cannot be conceived as otherwise) and universal, in the sense that it admits of
no exceptions. In critical philosophy, epistemological Rationalism finds
expression in the claim that the mind imposes its own inherent categories or
forms upon incipient experience (see below Epistemological Rationalism in modern
philosophies ). |
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In ethics Rationalism holds the position
that reason, rather than feeling, custom, or authority, is the ultimate court of
appeal in judging good and bad, right and wrong. Among major thinkers, the most
notable representative of rational ethics is Immanuel
Kant, who held that the way to judge an act is to check its
self-consistency as apprehended by the intellect: to note, first, what it is
essentially, or in principle--a lie, for example, or a theft--and then to
ask if one can consistently will that the principle be made universal. Is theft,
then, right? The answer must be "No," because, if theft were generally
approved, no one's property would be his own as opposed to anyone else's and
theft would then become meaningless; the notion, if universalized, would thus
destroy itself, as reason, by itself, is sufficient to show. (see also categorical imperative) |
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In religion Rationalism commonly means
that all of man's knowledge comes through the use of his natural faculties,
without the aid of supernatural revelation.
"Reason" is here used in a broader sense, referring to man's cognitive
powers generally, as opposed to supernatural grace or faith--though it is also
in sharp contrast to so-called existential approaches to truth. Reason, for the
Rationalist, thus stands opposed to many of the religions of the world,
including Christianity, which have held that the divine has revealed itself
through inspired persons or writings and which have required, at times, that its
claims be accepted as infallible, even when they do not accord with natural
knowledge. Religious Rationalists hold, on the other hand, that if the clear
insights of man's reason must be set aside in favour of alleged revelation, then
human thought is everywhere rendered suspect--even in the reasonings of the
theologians themselves. There cannot be two ultimately different ways of
warranting truth, they assert; hence Rationalism urges that reason, with its
standard of consistency, must be the final court of appeal. Religious
Rationalism can reflect either a traditional piety, when endeavouring to display
the alleged sweet reasonableness of religion, or an anti-authoritarian temper,
when aiming to supplant religion with the "goddess of reason." (see
also religion, philosophy of) |
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The first Western philosopher to stress
rationalist insight was Pythagoras, a shadowy
figure of the 6th century BC. Noticing that, for a right triangle, a square
built on its hypotenuse equals the sum of those on its sides and that the
pitches of notes sounded on a lute bear a mathematical relation to the lengths
of the strings, Pythagoras held that these harmonies
reflected the ultimate nature of reality. He summed up the implied metaphysical
Rationalism in the words "All is number." It is probable that he had
caught the Rationalist's vision, later seen by Galileo, of a world governed
throughout by mathematically formulable laws. (see also number
system) |
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The difficulty in this view, however, is
that, working with universals and their relations, which, like the
multiplication table, are timeless and changeless, it assumes a static world and
ignores the particular, changing things of daily life. The difficulty was met
boldly by the Rationalist Parmenides, who
insisted that the world really is a static whole and that the realm of change
and motion is an illusion, or even a self-contradiction. His disciple Zeno
of Elea further argued that anything thought to be moving is confronted
with a row of points infinite in number, all of which it must traverse; hence it
can never reach its goal, nor indeed move at all. Of course, perception tells us
that we do move; but Zeno, compelled to choose between perception and reason,
clung to reason. |
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The exalting of rational insight above
perception was also prominent in Plato (c.
427-347 BC). In the Meno,
Socrates dramatized the innateness of knowledge by calling upon an
illiterate slave boy and, drawing a square in the sand, proceeding to elicit
from him, step by step, the proof of a theorem in geometry
of which the boy could never have heard (to double the size of a square, draw a
square on the diagonal). Such knowledge, Rationalists insist, is certain,
universal, and completely unlearned. |
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Plato so greatly admired the rigorous
reasoning of geometry that he is alleged to have inscribed over the door of his
Academy "Let no one unacquainted with geometry enter here." His famous
"ideas" are accessible only to reason,
not to sense. But how are they related to sensible things? His answers differed.
Sometimes he viewed the ideas as distilling those common properties of a class
in virtue of which one identifies anything as a member of it. Thus what makes
anything a triangle is its having three straight sides; this is its essence. At
other times, Plato held that the idea is an ideal, a non-sensible goal to which
the sensible thing approximates; the geometer's perfect triangle "never was
on sea or land," though all actual triangles more or less embody it. He
conceived the ideas as more real than the sensible things that are their shadows
and saw that the philosopher must penetrate to these invisible essences and see
with the eye of his mind how they are linked together. For Plato they formed an
orderly system that was at once eternal, intelligible, and good. |
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Plato's successor Aristotle
(384-322 BC) conceived of the work of reason in much the same way, though he did
not view the ideas as independent. His chief contribution to Rationalism lay in
his syllogistic logic, regarded as the chief
instrument of rational explanation. Man explains particular facts by bringing
them under general principles. Why does one think Socrates will die? Because he
is a man, and man as such is mortal. Why should one accept the general principle
itself that all men are mortal? In human experience such principles have so far
held without exception. But the mind cannot finally rest in this sort of
explanation. Man never wholly understands a fact or event until he can bring it
under a principle that is self-evident and necessary; and he then has the
clearest explanation possible. On this central thesis of Rationalism, the three
great Greeks were in accord. |
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Nothing comparable in importance to
their thought appeared in Rationalistic philosophy in the next 1,800 years,
though the work of Thomas Aquinas in the 13th
century was an impressive attempt to blend Greek Rationalism and Christian
revelation into a single harmonious system. |
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Thoroughgoing Rationalism is to be found
only in the philosophical tradition that has come down from Greece; the
mysticism of India and the practicality of China have offered a less congenial
soil for it. The nearest parallels to it in Eastern thought are found in the
work of the Indian philosopher Shankara, who flourished about AD
800, and in that of the Chinese sage Chu-Hsi
(1130-1200). Both were commentators on the ancient scriptures of their lands;
and in ordering the scattered insights of these sources into intelligible
systems, they did for their respective peoples something like what Aquinas did
for the West in his harmonizing of Greek with Christian thought. Shankara
held, as Sir Sarvepalli Radhakrishnan has expressed it, that "the Absolute
is the unattainable goal towards which the finite intellect strives."
Perception is confined to what is transient and fragmentary; reason rises to
truth that is timeless and universal; but even reason falls short of full
understanding, which is achieved, if at all, only through mystical vision. Chu
Hsi, who has influenced Chinese thought for the past six centuries, was a
disciple of Confucius, though he had a stronger speculative interest than his
master. He held that in all human minds a single reason was at work, which he
called "the Way." All things were in some degree manifestations of it,
and hence the understanding of the world lay in more complete identification
with it. (see also Shankara) |
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The first modern Rationalist was René
Descartes (1596-1650), who was an original mathematician whose ambition was to
introduce into philosophy the rigour and clearness that delighted him in
mathematics. He set out to doubt everything in
the hope of arriving in the end at something indubitable. This he reached in his
famous cogito
ergo sum, "I think, therefore I am"; for to doubt one's own
doubting would be absurd. Here then was a fact of absolute certainty, rendered
such by the clearness and distinctness with which it presented itself to his
reason. His task was to build on this as a foundation, to deduce from it a
series of other propositions, each following with the same self-evidence. He
hoped thus to produce a philosophical system on which men could agree as
completely as they do on the geometry of Euclid. The main cause of error, he
held, lay in the impulsive desire to believe before the mind is clear. The
clearness and distinctness upon which he insisted was not that of perception but
of conception, the clearness with which the intellect grasps an abstract idea,
such as the number three, or its being greater than two. (see also clarity
and distinctness, concept formation) |
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His method was adopted in essentials by
both Benedict Spinoza (1632-77) and G.W.
Leibniz (1646-1716), who agreed that the framework of things could be
known by a priori thinking. They differed from him, however, in their starting
points. What was most undeniable to Spinoza was not the existence of his self
but that of the universe, called by him Substance.
From the idea of Substance, and with the aid of a few definitions and axioms, he
derived his entire system, which he set forth in his Ethics
in a formal fashion patterned after Euclid's geometry. Still, for both
Spinoza and Leibniz much in nature remained stubbornly opaque. Leibniz
distinguished necessary truths, those of which the opposite is impossible (as in
mathematics), from contingent truths, the opposite of which is possible, such as
"snow is white." But was this an ultimate distinction? At times
Leibniz said boldly that if only man knew enough, he would see that every true
proposition was necessarily true--that there are no contingent truths, that snow
must be white. |
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How, then, does reason operate and how
is it possible to have knowledge that goes beyond experience? A new answer was
given by Immanuel Kant (1724-1804) in his Critique
of Pure Reason, which, as he said, involved a Copernican revolution
in philosophy. The reason man can be certain that his logic and mathematics will
remain valid for all experience is simply that their framework lies within his
own mind; they are forms of arrangement imposed from within upon the raw
materials of sensation. Man will always find things arranged in certain patterns
because it is he who has unwittingly so arranged them. Kant held, however, that
these certainties were bought at a heavy price. Just because a priori insights
are the reflection of man's own mind, he cannot trust them as a reflection of
the world outside himself. Whether the rational order in which man arranges his
sensation--the order, for example, of time, space, and causality--represents an
order holding among things-in-themselves (German Dinge-an-sich)
he cannot hope to know. Kant's Rationalism was thus the counterpart of a
profound Skepticism. (see also thing-in-itself) |
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G.W.F. Hegel
(1770-1831), the most thoroughgoing of Rationalist thinkers, attempted to break
out of this Skepticism. He argued that to think of an unknowable is already to
bring it within the sphere of what is known and that it is meaningless to talk
of a region in which logic is invalid. Further, to raise the question
"Why?" is to presume that there is an intelligible answer to it;
indeed the faith of the philosopher must be that the real is the rational and
the rational real, for this faith is implicit in the philosophic enterprise
itself. As an attempt to understand and explain the world, philosophy is a
process of placing something in a context that reveals it as necessary. But this
necessity is not, as earlier Rationalists had supposed, an all-or-nothing affair
issuing in a self-evident finality. Understanding is a matter of degree. What
alone would wholly satisfy thought is a system that is at once all-inclusive and
so ordered that its parts entail each other. Hegel believed that the universe
constitutes such a whole and, as an idealist, held that it is a single, absolute
mind. To the degree that the philosopher embodies and realizes this mind, his
own mind will achieve both truth and reality. Indeed, the advance of
civilization reflects the enlarging presence and control of such a system in the
human spirit. Broadly similar Rationalistic systems were developed in England by
F.H. Bradley (1846-1924) and Bernard
Bosanquet (1848-1923) and in America by Josiah
Royce (1855-1916). (see also Absolute
Idealism) |
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The views of Kant were presented above
as typical of this position (see above, Types
and expressions of Rationalism ). But
few moralists have held to ethical Rationalism in this simple and sweeping form.
Many have held, however, that the main rules of conduct are truths as
self-evident as those of logic or mathematics. Lists of such rules were drawn up
by Ralph Cudworth and Henry
More among the Cambridge Platonists of the 17th century, who were noted
for holding that moral principles were intrinsic to reality; and in the 18th
century Samuel Clarke and Richard
Price, defenders of "natural law" ethics, and the "common
sense" moralist Thomas Reid also presented
such lists. A 20th-century revision of this Rationalism has been offered by the
Rational Intuitionists H.A.
Prichard and Sir David Ross of Oxford
under the name of deontology (Greek deon, "duty"),
which respects duty more than consequences. Ross provides a list of propositions
regarding fidelity to promises, reparation for injuries, and other duties, of
which he says: "In our confidence that these propositions are true there is
involved the same trust in our reason that is involved in our trust in
mathematics." What is taken as self-evident, however, is not specific rules
of conduct, but prima facie duties--the claims that some types of action have on men
because of their nature. If a man is considering whether to repay a debt or to
give the money to charity, each act has a self-evident claim on him; and their
comparative strengths must be settled by a rational intuition. (see also deontological
ethics ) |
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The most influential variety of
20th-century ethical Rationalism has probably been the Ideal
Utilitarianism of the British moralists Hastings Rashdall (1858-1924) and
G.E. Moore (1873-1958). Both were teleologists
(Greek telos, "end") inasmuch as they held that what makes an act
objectively right is its results (or end) in intrinsic goods or evils. To
determine what is right, reason is required in two senses: firstly, the
inference to the consequences is an act of inductive reasoning; secondly, the
judgment that one consequence is intrinsically better than another is a priori
and self-evident. Moore thought that there is a single rule for all conduct--one
should so act as to produce the greatest good--and that this is also a principle
self-evident to reason. |
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Stirrings of religious Rationalism were
already felt in the Middle Ages regarding the Christian revelation. Thus the
skeptical mind of Abelard (1079-1142) raised
doubts by showing in his Sic
et Non ("Yes and No") many contradictions among beliefs
handed down as revealed truths by the Church Fathers. The greatest of the
Medieval thinkers, Thomas Aquinas (1225-74), was a Rationalist in the sense of
believing that the larger part of revealed truth was intelligible to and
demonstrable by reason, though he thought that a number of dogmas opaque to
reason must be accepted on authority alone. |
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Religious Rationalism did not come into
its own, however, until the 16th and 17th centuries, when it took two chief
forms: the scientific and the philosophic. |
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Galileo
(1564-1642) was a pioneer in astronomy and the founder of modern dynamics. He
conceived of nature as governed throughout by laws statable with mathematical
precision; the book of nature, he said, is "written in mathematical
form." This notion not only ruled out the occasional appeal to miracle; it
also collided with dogmas regarding the permanent structure of the world--in
particular with that which viewed the Earth as the motionless centre of the
universe. When Galileo's demonstration that the Earth moves around the Sun was
confirmed by the work of Newton and others, a battle was won that marked a
turning point in the history of Rationalism, since it provided a decisive
victory in a crucial case of conflict between reason and apparently revealed
truth. |
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The Rationalism of Descartes, as already
shown, was the outcome of philosophic doubt rather than of scientific inquiry.
The self-evidence of the cogito, seen
by his "natural light," he made the ideal for all other knowledge. The
uneasiness that the church soon felt in the face of such a test was not
unfounded, for Descartes was in effect exalting the natural light into the
supreme court even in the field of religion. He argued that man's guarantee
against the possibility that even this natural light might deceive him lay in
the goodness of the Creator. But then to prove this Creator, he had to assume
the prior validity of the natural light itself. Logically, therefore, the last
word lay with rational insight, not with any outside divine warrant. Descartes
was inadvertently beginning a Copernican revolution in theology. Before his
time, the truths regarded as most certain were those accepted from revelation;
afterwards these truths were subject to the judgment of human reason, thus
breaking the hold of authority on the European mind. (see also cogito,
ergo sum) |
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The Rationalist attitude quickly spread,
its advance forming several waves of general interest and influence. The first
wave occurred in England in the form of Deism.
Deists accepted the existence of God, but spurned supernatural revelation. The
earliest member of this school, Lord Herbert of
Cherbury (1583-1648), held that a just God would not reveal himself to a
part of his creation only and that the true religion is thus a universal one,
which achieves its knowledge of God through common reason. The Deistic
philosopher John Toland (1670-1722), in his Christianity
Not Mysterious, sought to show that "there is nothing in the
Gospels contrary to reason, nor above it"; any doctrine that is really
above reason would be meaningless to man. Attacking revelation, the freethinking
polemicist Anthony Collins (1676-1729)
maintained that the prophecies of the Old Testament failed of fulfillment; and
the religious controversialist Thomas Woolston
(1670-1733) urged that the New Testament miracles, as recorded, are incredible. Matthew
Tindall (1657-1733), most learned of the English Deists, argued that the
essential part of Christianity is its ethics, which, being clearly apparent to
natural reason, leaves revelation superfluous. Thus the Deists, professing for
the most part to be religious men themselves, did much to reconcile their public
to the free play of ideas in religion. |
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The second wave of religious
Rationalism, less moderate in tone and consequences, was French. This wave,
reflecting an engagement with the problem of natural evil, involved a decay in
the natural theology of Deism such that it merged eventually with the stream
that led to materialistic Atheism. Its moving
spirit was Voltaire (1694-1778), who had been
impressed by some of the Deists during a stay in England. Like them, he thought
that a rational man would believe in God but not in supernatural inspiration.
Hardly a profound philosopher, he was a brilliant journalist, clever and
humorous in argument, devastating in satire, and warm in human sympathies. In
his Candide and in many other
writings, he poured irreverent ridicule on the Christian scheme of salvation as
incoherent and on the church hierarchy as cruel and oppressive. In these
attitudes he had the support of Diderot
(1713-84), editor of the most widely read encyclopaedia that had appeared in
Europe. The Rationalism of these men and their followers, directed against both
the religious and the political traditions of their time, did much to prepare
the ground for the explosive French Revolution. (see also evil,
problem of) |
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The next wave of religious Rationalism
occurred in Germany under the influence of Hegel, who held that a religious
creed is a halfway house on the road to a mature philosophy, the product of a
reason that is still under the sway of feeling and imagination. This idea was
taken up and applied with learning and acuteness to the origins of Christianity
by David Friedrich Strauss (1808-74), who
published in 1835, at the age of 27, a remarkable and influential three-volume
work, Das Leben
Jesu (The Life of Jesus,
Critically Examined, 1846). Relying largely on internal inconsistencies in
the Synoptic Gospels, Strauss undertook to prove these books to be unacceptable
as revelation and unsatisfactory as history. He then sought to show how an
imaginative people innocent of either history or science, convinced that a
Messiah would appear, and deeply moved by a unique moral genius, inevitably wove
myths about his birth and death, his miracles, and his divine communings. (see
also Hegelianism) |
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Strauss's thought as it affected
religion was continued by the philosophical historian Ernest
Renan (1823-92) and as it affected philosophy by the humanist Ludwig
Feuerbach (1804-72) of the Hegelian left. Renan's Vie
de Jésus (1863; Life
of Jesus) did for France what Strauss's book had done for Germany,
though the two differed greatly in character. Whereas Strauss's work had been an
intellectual exercise in destructive criticism, Renan's was an attempt to
reconstruct the mind of Jesus as a wholly human person--a feat of imagination,
performed with a disarming admiration and even reverence for its subject and
with a felicity of style that gave it a large and lasting audience. Feuerbach's Wesen
des Christentums (1841; Eng. trans. by George Eliot, Essence
of Christianity, 1853) applied the myth theory even to belief in the
existence of God, holding that "man makes God in his own image." |
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The fourth wave occurred in Victorian
England, following the publication in 1859 of Darwin's Origin of Species. This book was
taken as a challenge to the authority of Scripture because there was a clear
inconsistency between the Genesis account of creation and the biological account
of man's slow emergence from lower forms of life. The battle raged with
bitterness for several decades but died away as the theory of evolution
gained more general acceptance. |
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With increasing freedom of thought and
wider acceptance of scientific views, Rationalism in religion has lost its
novelty and much of its controversial excitement. To the contemporary mind, it
is too obvious to warrant debate that reason and revelation
cannot both qualify as sources of ultimate truth for, were they to conflict,
truth itself would become self-contradictory. Hence theologians have sought
accommodation through new interpretative principles that discern different
grades of authenticity within the Scriptures and through new views of religious
truth, existential rather than cognitive, that turn from propositional dogmas to
the explication of lived human existence. Criticism of supernaturalism, however,
is still carried on by such societies as the Rationalist Press Association, in
Great Britain, and the Humanist Association, in the United States. (see also religion,
philosophy of) |
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Western Philosophical
Schools and Doctrines |
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Rationalism in ethics has suffered its
share of criticism. Regarding its lists of rules--on the keeping of promises,
the return of loaned goods, etc.--it has been argued, for example, that if they
were specific enough to be useful (as in the rule against lying or stealing),
they would tend to have exceptions--which no rule laid down by reason ought to
have. On the other hand, if without exceptions, they would often prove to be tautologies:
the rule of justice, for example, that we should give everyone his due would
then mean only that we should give him what is justly his. After enduring a
period of eclipse, however, during which noncognitive theories of ethics
(emotive and existential) and relativism had preempted the field, rationalistic
views, which agree in holding that moral standards do not depend upon the
varying attitudes of persons or peoples, were receiving renewed attention in the
mid-20th century. Prominent among these developments has been the "good-reasons"
approach taken by the broadly gauged scholar Stephen
Toulmin, by Kurt Baier, and others, which examines the contexts of
various moral situations and explores the kinds of justification appropriate for
each. |
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Typical of the ways of reasoning
employed by Rationalists are two approaches taken to the metaphysical doctrine
that all things are connected by internal relations:
one a logical, the other a causal argument. An internal relation is one that
could not be removed without affecting the terms themselves between which the
relation holds. The argument runs: Everything is related to everything else at
least by the relation "A is different
from B." But difference is itself an internal relation, since the terms
could not remain the same if it were removed. Hence everything is so connected
with everything else that it could not be what it is unless they were what they
are. The appeal to internal relations played an important part in the
philosophies of Hegel, F.H. Bradley, and A.N. Whitehead
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The other line of argument is causal.
Every event, it is maintained, is connected with every other, either directly or
indirectly. Sir James Jeans argued that if the
law of gravitation is valid, a man cannot crook his little finger without
affecting the fixed stars. Here the causal relation is direct. It can also be
shown that seemingly unrelated events are joined indirectly through their common
connection with some remote historical event, by a chain of events leading back,
for example, to Columbus' discovery of America. But if this had been different,
all of its consequences would presumably have been different; thus an indirect
and internal relation proves to have been present. (see also causality) |
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Many Rationalists have held with Spinoza
that the causal relation is really a logical one--that a causal law, if
precisely stated, would reveal a connection in which the character of the cause
logically necessitates that of its effect; and if this is true, they maintain,
the facts and events of the world must thus compose a single rational and
intelligible order. |
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In the 20th century, such Rationalism
met with a new and unexpected difficulty presented by quantum physics. According
to the indeterminacy principle, formulated in
1927 by the German physicist Werner Heisenberg,
it is impossible to discover with precision both the position and the velocity
of a moving electron at the same time. This implies that definite causal laws
for the behaviour of these particles can never be attained, but only statistical
laws governing the behaviour of immense aggregates of them. Causality, and with
it the possibility of rational understanding, seemed to be suspended in the
subatomic world. Some interpreters of the new physics, however, notably Max
Planck, Albert Einstein, and Bertrand Russell, sustained the hopes of the
Rationalists by insisting that what was excluded by the indeterminacy principle
was not the fact of causality in this realm, but only the precise knowledge of
it. |
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Indeed, some leaders of 20th-century
science took the new developments in physics as on the whole supporting
Rationalism. Protons and electrons, they contended, though beyond the reach of
the senses, can still be known; and their behaviour, at least in groups, is
increasingly found to conform to mathematical law. In 1932, Sir James Jeans, an
astrophysicist and popularizer of science, said with a curious echo of Galileo,
"the universe appears to have been designed by a pure mathematician."
(see also metaphysics) |
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At first glance the claim of Empiricism
that knowledge must come from sense experience seems obvious: how else could one
hope to make contact with the world around one? Consequently, Rationalism has
been sharply challenged--in the 19th century by the Empiricism of John
Stuart Mill (1806-73) and in the 20th by that of the Logical
Positivists. Mill argued that all a priori certainties are illusory: why
does man believe, for example, that two straight lines cannot enclose a space?
Is it because he sees it as logically necessary? No; it is because he has
experienced so long and so unbroken a row of instances of it -- a new one
whenever he sees the corner of a table or the bordering rays of a light
beam--that he has formed the habit of thinking in this way and is now unable to
break it. A priori propositions, Mill claimed, are merely empirical statements
of very high generality. (see also a
priori knowledge) |
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This theory has now been abandoned by
most Empiricists themselves. Its implication that such statements as "2 + 2
= 4" are only probably true and may have exceptions has proved quite
unconvincing. The Rationalist's rejoinder is that one cannot, no matter how hard
one tries, conceive 2 + 2 as making 5; for its equalling 4 is necessary. But a
priori knowledge is also universal. Neither of these two characteristics can be
accounted for by sense experience. That a crow is black can be perceived, but
not that it must be black or that crows will always be black; no run of
perceptions, however long, could assure us of such truths. On the other hand, a
priori truths can be seen with certainty--that if a figure, for instance, is a
plane triangle within a Euclidean space, its angles must and always will equal
two right angles. |
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Perhaps the most formidable challenge to
Rationalism has come in the 20th century from such Logical Positivists as the
Oxford Empiricist A.J. Ayer (1910- ) and Rudolf
Carnap (1891-1970), who had been a central figure in the Vienna Circle,
where this movement first arose. Unlike Mill, they accepted a priori knowledge
as certain; but they laid down a new challenge--the denial of its philosophic
importance. A priori propositions, they said, are (1) linguistic, (2)
conventional, and (3) analytic: (1) They are statements primarily of how one
proposes to use words; if one says that "a straight line is the shortest
line between two points," this merely reports one's definition of
"straight" and declares one's purpose to use it only of the shortest.
(2) Being a definition, such a statement expresses a convention to which there
are alternatives; it may be defined in terms of the paths of light rays if one
chooses. (3) The statement is analytic in that it merely repeats in its
predicate a part or the whole of the subject term and hence tells nothing new;
it is not a statement about nature but about meanings only. And since
Rationalistic systems depend throughout upon statements of this kind, their
importance is illusory. (see also analytic proposition ) |
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To this clear challenge some leading
Rationalists have replied as follows: (1) Positivists have confused real with
verbal definition. A verbal definition does indeed state what a word means; but
a real definition states what an object is, and
the thought of a straight line is the thought of an object, not of words. (2)
The Positivists have confused conventions in thought with conventions in
language. One is free to vary the language in which a proposition is expressed,
but not the proposition itself. Start with the concept of a straight line, and
there is no alternative to accepting it as the shortest. (3) Some a priori
statements are admittedly analytic, but many are not. In "whatever is
coloured is extended," colour and extension are two different concepts of
which the first entails the second, but is not identical with it in whole or
part. Contemporary Rationalists therefore hold that the a priori has emerged
victorious from the Empiricists' efforts to discredit such knowledge and the
Positivists' attempts to trivialize it. |
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(B.Bl.) |
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