On Skepticism

May 032004
Authors: Brent Ables

Last week, I wrote about the problem of relying on the

information we get from a few select individuals in the reporting

world. This is especially a concern when many in the media seem to

lack any sort of moral devotion to their profession. I decided to

follow that piece up (and indulge myself) with a broader

investigation of knowledge and doubt. If you like this sort of

thing, read on.

“Skepticism,” said the 18th century philosopher David Hume, “is

a malady which can never be radically cured, but must return upon

us every moment, however we may chase it away.”

Certainly, we can trust Hume as an authority on the subject if

we can trust anyone. In the course of his rigorous philosophy he

was able to offer compelling and sound arguments against many of

the things we most take for granted: the existence of matter, the

law of cause and effect and even the self.

But speaking more generally, is it true that we are faced with

skepticism every moment of our lives? Is it true, as some have

maliciously argued, that the world is only an illusion and true

knowledge is impossible?

One’s initial reaction to this sort of proposition is a

common-sense one; of course knowledge is possible, we say. There

would, for example, be no foundation for a university if knowledge

was not obtainable. On the surface, this belief in the reality of

knowledge seems to make philosophical skeptics look merely foolish,

or, at the worst, dangerous.

To truly understand the problem of skepticism, though, I think

we have to look beyond what our intuition and “common sense” tells


Consider, first, that everything we claim to know about the

outside world comes to us by means of our five senses. The question

that arises immediately from this fact is: how do we know our

senses are accurately reflecting the world? How do we know, for

example, that we are not merely brains in a vat somewhere with

electronic signals being pumped into our cerebrum to give us the

illusion of physical existence?

This “Matrix”-esque situation, however, does not exhaust the

possibilities. For one thing, it presupposes the idea that there

are actually things called brains and that what we call “sensory

perceptions” actually exist.

Certainly, there is no empirical way to verify the correctness

of what we perceive. People attempt to argue against this by

postulating the existence of other beings with which we can reach

consensus, and therefore conviction about sensory things.

For example, if I see an apple and another person tells me they

see it as well, I assume that this somehow proves the existence of

the apple. But the status of the supposed “other person” is the

same as that of any other thing in the outside world; that is, they

only exist as a function of my sensory interpretation of the world.

Ever since Descartes declared “I think, therefore I am,” the mind

has been set off against the outside world as self-evident.

It can be seen, then, that there is absolutely no way to prove

the existence of such a thing as the outside world. There are

truths we can legitimately call absolute, however.

For example, that 2 + 2 = 4 is a true proposition is something

that can not be argued with. It is in the very nature of these

conceptual entities – i.e. “2”, “4”, and the addition symbol – that

they yield this sum when combined in this manner. Even if no

numerals existed this would be the case.

To take another example, it is not possible to deny the

existence of circularity as a concept. Even if the material

universe did not exist and we had no word for circle, there is the

logical necessity of a conceptual object in which all points on the

outside of the shape lie at equal distances from the center. To put

this another way, try to imagine a square circle. One can not do it

of course, for the two are logically contradictory – this is

because of the logical necessity of a circle’s incompatibility with

a square.

Thus, we can have knowledge at least in the sense of

understanding logical relations. But this does not answer the

question of how I can know that the pizza I am eating or the girl I

am kissing is not merely a figure in a dream, or that my entire

life is not merely a passing thought in the mind of an old man.

Still: when I go out into the world, I will adhere to the laws

of science and treat my friends as the same people they were


Can I prove the validity of either of these actions? As I

already argued, this is impossible, but then again it may not be

necessary. Whatever the ontological status of the pizza I will eat

tonight, I can still believe that it tastes good. The entire span

of our lives, it seems, is practiced according to this same naive


Brent is a freshmen studying philosophy, surpisingly.

 Posted by at 5:00 pm

Sorry, the comment form is closed at this time.