Logic sucks

Neven Sesardic
(Lingnan University, Hong Kong: sesardic@ln.edu.hk)

Logic is praised as a field

where all is crystal clear,

where after you learn the basics

you can just sit and sip your beer.

So after a few cans of lager

and grasping the logic's ABC

there’s only one question left:

p or not to p?

Logic is supposed to teach you

about validity, dude:

how to start from premises,

and what from them to conclude.

If an argument is valid,

true can never lead to wrong.

This rule has no exceptions,

not even in Hong Kong.

When properly conducted

the method of deduction

should have a lower error rate

than performing liposuction.

Yet though deductive inference

is supposed to be safe and sound,

often things get screwed up

and there are glitches all around.

Some syllogisms that Aristotle

called valid and even great

are the forms of reasoning

that now logicians simply hate.

What should a poor student think,

seeing that experts can't agree:

the greatest ancient mind

and those big shots from MIT.

Sometimes it gets much worse,

and it's not a pretty scene

when the answer is “Yes and no”,

or something in between.

Say, the number of truth values

is set at exactly 2,

since any given statement

is either false or true.

But then, we are later told,

the number might well be higher:

3, 4, or 37,

or infinity—if you desire.

Which figure should be used then?

It seems that no one knows.

In Feyerabend's words:

Hurray, anything goes!

Embracing a contradiction

was once an absolute no-no,

but now, I regret to inform you,

this is not longer so.

The logical rule number one

was rejection of "A and not-A",

yet this is today accepted

as perfectly OK.

The sect of dialetheism

and particularly its high priest

rejoice in this absurdity

without worrying in the least.

Hello to unreason!

Consistency, good-bye!

We lost any firm foundation

on which we could rely.

In view of this total chaos

it's unwise too much to pay

for studying the subject

in such horrible disarray.

Hence you need not go to Stanford,

or Berkeley or Lingnan U,

for surely such nonsense is also offered

at some college in Timbuktu.