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What

Dialectical logic»should help us-ia two

ways. It should:teach us when to use o
logic and argue as though a thing w

rdinary
ere un-

changeable and when to beware of the

fallacies into

t
i

A” READER asks me to write
: » “Logic” is derived from the Gr
| nd originally meant the art of using
hat an inference based on them is vali

© the use of other symbols be-

a ides words.’

ior

ry

Of course words can, and

i “ometimes should, be used il-

© ogically. Shakespeare was
f ustified in writing of: “Ser-
faons in ‘stones, books in the
bunnine: brook,” though “Ser-
jnons in books, stones in the
Punning brooks,’ would have
seen more logical. But we must
be yery careful in switching
= ver from one use of words to

' nother.

Logic was founded by the
meient Greeks, and systema-
ized by ‘Aristotle. The mediae-
pal philosophers - merely devel-
) ped Aristotle’s “ideas, but in
‘he last 150 "years logic has

‘Town along several new lines.
hese include dialectical logic,
FP eveloped by Hegel, Marx, En-
© els and others, symbolic logic,

eveloped by Boole, Peano,
‘ussell, Whitehead, and many
and the logic of
developed by La-
other mathemati-

|vin& men,
robability,

Mace and

fe ans. These different branches

re not really distinct.

"HE traditional logic has its

uses and its dangers. Its

® reatest use is to teach the ac-
Purate use of words. For ex-
\mple, T do not believe that the
} ewish law is divinely inspired
1nd should be obeyed in all
ases. If the “Jew”
mleans a man or woman who
elieves this, I want to see few-

'r Jews.

word

| This does not mean that I am
© nti-Semitic. I think people of
‘ewish origin have every right
> be proud of a law which
out 3,000 years ago, included
ne text, “Thou shalt not de-
| ver unto his master the ser-
vant which is escaped from his
saster unto thee’ (Deuteron-
imy 24, 65), “and to use his
imide-to help them to work for
"aman liberation.

sd

tich this leads us.

( - By Prof. J. B. Ss. Haldane

d. It is now applied

If that is what “Jew” means,
I wish there were more Jews.

Unfortunately both J ews and™

Gentiles use the word “Jew?
in both these senses in the same
argument, and this leads to

misunderstanding, and worse.

The danger of formal logic
is that it leads us to believe
that classifications are sharp,
either in space or time. Our
law is based on formal logic.
A jury has te say that a man
is either guilty or not guil-
ty of a crime. In practice,
everyone knows that there
are degrees of guilt, but a

jury cannot assess them, and ~

im consequence injustice is
done.

Similarly, one can generally
count the people in a room ac-

curately, but no one could count .

the populations of London ac-
curately,
ment some are being born and
others dying; and neither birth
nor death is instantaneous.

Formal logic is
with relations which can be ex-
pressed by predication; for ex-
ample, “Montgomery is a field-
marshal.’ “No women are
field-marshals” from which we
can deduce that Montgomery is
not a woman. It helps us to
avoid fallacious arguments, for
example, “Bifty Wreelshmen
were convicted of theft, there-
fore Welshmen are
(meaning that all Welshmen

are thieves).

YMBOLIC logic, which uses
symbols rather like those of
algebra, deals with other rela-
tions, and classifies them. For

‘example, if A is like B, then

Bis like A. Such relations are
called reflexive. If A is larger
than B, and B larger than G,
then A is larger than C. Such
relations are called transitive.
Symbolic logic has proved valu-
able in laying the foundations

of mathematics.

en elementary logic.:
eek “logos’’, a word, |
words accurately, so

“run, this logic is quantative.

693 days.
because at any mo-

concerned |

thieves” -

Va

@

PROF. J. B. S: HALDANE
Eminent British Scientist

The logic of: probability is

nearer to ‘teal life. When f

_ say: “If I get to the station by

7:20 I shall be in time for

work,’ I mean that I am so

- likely to be in time that i can
In’ the long _
It -

take the chance.

is’ sensible to take a risk of one
in a thousand of losing the train

in order to finish breakfast, and

foolish to take a chance of one
in a thousand of losing one’s
life for the same reason:

If I run a risk of one in a
thousand of losing my train (or
my life) every day, l am rather
more likely than not to lose it in
very important, not only for
States and ‘large businesses,
but for the foundations of sci-

enee, where chemists and phy-—

sicists deal with millions of

_atoms, and biologists. with mil-
lions of cells or of animals or

plants.

IALETICAL | logic is. spé-
concerned with .
Words, and the ideas ©

cially.
change.
for which they stand, change
their So do
things and processes which
they symbolize. Hegel saw that

meanings.

the laws of change were simi--

lar, as they must be if ideas
and words correspond to real-
ity. -

But’as Marx put it, he stood
on his head, by thinking that
ideas determined reality, in-
stead of the other way round.
But as. ideas-are simpler than
the reality for which they stand,
it is easier to see how they
change, and hence the word
“dialectical,” which applies to
Marx’s theory. of the world, is
taken from logic.

“the

This kind of logic is:

‘the -

DOA Features, November 25 — Page 13

Is Logic? —

GOOD way of understanding

what a word means is to
argue about it. Smith says that
man has a natural right to
property. Jones says that prop-
erty is. theft: If each tries to
understand the other, they will

‘gettme at the truth is called
method. ‘The

je dialectical
word comes from the same root

as “dialogue.”

Just the same is true of a
real thing.

transcience.

permanent than a lightning

flash, and less so than a moun-—

tain. But nothing is instan-
taneous or lasts forever.- Simi-

“larly the boot would-be no good

if it were as hard as iron or

as soft as putty.

Further, ideas change be-

cause they involve internal
contradictions. Our word “just”
is derived from the Latin rus,”
meaning law, and originally
meant “according to law.’ Obe-
dience to laws which can be al-
tered by the State is a great ad-
vance on obedience either to im-

pulse or to traditions which are

thought to be unalterable. But

see that a man’s claim to own ~
his ‘socks is more unreasonable z :
eesa RS Glin 2) Ou a ule 4 Bete same kind of thing hap-
dred square miles of land. eae

‘Smith and Jones are’both right i
up toa point. This method of

>= Tiver cannot ‘stay put.
“moves soil and rocks in some

Hiverythine. that’
exists has both permanence and
A boot is more

‘

after men had got accustomed
to obeying law, they began to
see that justice went beyond
the law, and that a law could
be unjust. The idea of injus-
tice had developed so as to
negate its original meaning.

¥

pens in_nature..An egg
eannot.stay put. It must.either

‘die.or develop into a bird: A

it re-

places, and deposits them in
others. Whe egg and the river
develop by negating them-
selves. Dialectical logic should
help us in two'ways. It should
teach us when to use ordinary
logic, and argue about a thing
as if it were unchangeable,
and when to beware of the fal-

Tacies into which this leads us.

And, what is more important,
it should teach us to understand
the process of change, and thus
to adapt ourselves to a rapidly.
changing world.

But just as we must learn or-
dinary mechanics before we can
understand the theory of rela-
tivity, and English grammar
before we can go on to com-
parative philology, it is well
worth learning a little tradi-
tional logic provided we do not
take it too seriously.

"CAR POOL, MILDRED! | SAID GAR POOL!"