Religious people, Christians among
them, claim to know something special about reality. This knowledge is of
a general kind, a class of truths. Epistemology asks whether it is
justified to assert that any class of knowledge is true.
Most of us don't worry about this question. Our
day-by-day knowledge either works or it doesn't. That is, for most of us
knowledge is "true" if it works and "untrue" if it doesn't. We "know", for
example, that gravity exists every time we take a fall.
But most of us tend to claim knowledge far beyond that which we can
experience at first-hand. We "know" that the moon isn't made of cheese even
though we haven't been there to verify the fact personally. So the question
naturally arises whether or not we are justified in claiming knowledge of a
class of truths called "astronomy" or any other class. In what sense, if at
all, can any of us claim to know anything about history, or science or
medicine or God?
Like so many such questions, they
were first recorded well over two thousand years ago. Plato in the fourth
century BC reports that Protagoras thought that whatever seems so to us, we
know. In that sense, "Man is the measure of all things." But Gorgias claimed
that there is no such thing as knowledge. It was left to Plato to try to
work out what knowledge is. He asked if it is the same thing as belief; if
it can be reached through reason; if it comes through the senses or by some
The debate has raged ever since with,
in my opinion, precious few substantial advances. One constant factor has
been skepticism - the doubt that knowledge can be taken for granted. It
seems to me that the character of proposed answers to "What is knowledge?"
has depended primarily on how subsidiary questions are framed.
example, if one supposes that knowledge allows and indeed requires the
statement of a truth with absolute certainty one is likely to come up with
one type of epistemological response. If knowledge is thought
of as provisional, always subject to change and discovery, then an entirely
different conclusion will result.
The history of
epistemological thought is long and complex.
- Plato (428-347) seems to have followed his
mentor, Socrates, in seeking knowledge of what is perfect. It's quite
clear to everyone that we never experience perfect justice, for example.
Justice is always tempered by error and unfairness. So he proposed that
we are able through reason to arrive at a concept (what he called the
"Form") of Justice. What we perceive through our senses are only
imperfect copies or representations of their Forms. We can "know" the
perfect, but can have only opinions about the imperfect.
- Aristotle (384-322) focused more on what
knowledge is than on whether or not it exists. He thought that we know
universal truth through particular truths. So through knowledge of a
number of particular dogs, we get to know what "a dog" is in a universal
sense. In turn we know each dog through our senses - or, more
accurately, through those senses which are able to perceive dogs. Thus
one kind of sense gives us perception of colour, and another kind of
sense a perception of heat and other senses other perceptions.
- Epicurus (341-270) and others also proposed
that we arrive at truth through our senses. Atoms affecting the sense
organs produce sensations, thus giving us information about the world.
This information eventually combines into a system of knowledge to
give us abstract ideas or what we know as concepts.
- Augustine (354-430) proposed that all knowledge exists first
as universals in the mind of God descending from there to lower kinds of
knowledge. Medieval thinkers developed this basic idea in various
Once the grip of Christian dogma began to loosen during the 16th and
17th centuries in Europe, the stage was set for an approach which depended
upon rational thought rather than theology.
Those like Descartes (1596-1650) , Spinoza
(1632-1677) and Leibniz (1646-1716) emphasised that all true knowledge is
derived by reason. They became known as Idealists.
Others like Locke (1632-1704), Berkeley (1685-1753) and Hume
(1711-1776) proposed that knowledge is derived first through sense
experience and then ordered by reason. Berkeley went the whole hog to
argue that there is no guarantee that anything other than our sense-data
is real. Hume thought that only what could be verified experimentally
could be called knowledge. They are broadly known as Realists.
Emmanuel Kant (1724-1804) tried to bring the two streams together by
proposing two types of distinction:
[a] What he called a priori knowledge is that truth which can be
worked out or verified independently of the senses. This sort of knowledge
involves only concepts. But concepts can be built upon experience
(sense-data) to give us a posteriori or empirical knowledge.
[b] Analytic judgements are those which attempt to explain
things. In doing so they don't give us any additional information about
reality. A false analytic judgement is one which involves contradiction.
In contrast, a synthetic judgement does give us information about
reality. If I deny the truth of such a judgement, I deny a fact rather
than point out a contradiction in an explanation.
In the late 19th and the 20th centuries, currents of thought have swung
this way and that. We're perhaps somewhat too close in the 21st century to
discern their long-term effect on the larger sea of human thought. My own
observations are that two main movements have begun to diverge
significantly from the past:
The dominance in the 20th century of science and technology has,
I think, encouraged us to recognise that distinction between the
subjective and objective may be of an entirely different character than
Thus what we call "subjective" is one way of perceiving the system we
know as the human body, and what we call "objective" merely another way.
They are not two separate and conflicting parts of reality. This in turn
places greater value on empirical data and the methods we use to reduce
or eliminate distorted interpretation of that data.
A greater understanding of how language operates has enabled us
to more clearly recognise its shortcomings and therefore to use ordinary
language more positively. Thinkers like Ludwig Wittgenstein (1889-1951)
have pointed out that it's not valid to invent special or "private"
language to "explain" anything. If one does this, it becomes impossible
to discern boundaries between such language and ordinary language.
Like most other approaches, analysis of the role of language in knowledge
can be taken too far. Some modern philosophers (like A J Ayer) have
reduced language as a way of conveying truth to the point where it is no
It is certainly true that all language is limited in its
ability to convey truth. Although
he would later modify his views, Ayer promoted a verification principle,
according to which a statement can be classed as knowledge if and only
if we know which sensory experiences would verify it. In effect
Ayer and others have exaggerated the weaknesses of language to the point
where it becomes terminally ill.
Christians and other religious people claim a special type of access to
truth. They assert that they have knowledge which has come to them from
God, either directly or via inspired writings. Such knowledge, if it can
be classed as such, is obviously outside the range of ordinary human
thought because it is supposed to have been revealed to us.
Revelation is knowledge only in the sense that it can be asserted or
denied. No other test can validly be applied to it, nor does it fit any of
the usual categories of knowledge. Reason can't be applied to it, since
its origins lie beyond reason. If it is information, its validity can't be
tested by any means except internal consistency - and even then, religious
people seem to display a remarkable tendency to tolerate contradictions
and inconsistencies within any body of revealed "knowledge".
Revelation, then, is essentially a claim to possess a type of knowledge
which is beyond question. It is absolute in the sense that because it
comes from God it must be true. That is, its objectivity can't be
questioned. If it has been revealed to us that we're sinful creatures,
then there's no point in questioning that truth. God is never wrong. I
think it's true to say that many, if not a majority, people in the West
today don't think of revelation as infallible knowledge.
The modern perception that all knowledge is provisional replaces the
medieval contention that some knowledge - revelation in particular - is
absolute. Uncertainty about what is known and what is illusion has
recently led some to what's generally known as "relativism",
I have a hammer in my hand. I know that it's use is to hit nails into
wood. But that knowledge is relative to my purpose. I might want to murder
my wife with it. In other words, what I know about a hammer is relative to
its use. The same distinction would apply to almost anything, even a
complex subject like "history". My "knowledge" of war if I'm fighting in
one will be very different from my "knowledge" of it if I'm studying it
Relativism, then, is the thesis that knowledge is not absolute, or even
just provisional, but relative to particular standpoints. A consequence is
that nobody can claim any knowledge except in terms of their own personal
experience. There may be clusters of very similar experiences which could
be labelled "knowledge", but none is intrinsically more valid than the
other. I can't say that I know something and you don't.
Even in science, knowledge may change according to its context. A
biologist perceives the living cell one way, the physicist in entirely
another way. They might even contest their differing scientific
conclusions. J W McAllister reports I Hacking as suggesting that there
might even exist "alternative styles of enquiry among which a choice is
open ... [a] view of scientific practice [which] readily accommodates
forms of relativism".
Relativism has been attacked by some as subverting the possibility of
knowing anything. If what I know may be untrue in relation to other
knowledge, they ask, what can anyone be certain of? What happens to
morality, for example? Who is to say that murder is morally wrong?
To sum up:
Language is imprecise. It can't be relied on to convey knowledge
either completely or entirely accurately. The point of logic is to test
that language is being used well.
Scientific knowledge is a type of knowledge which recognises our
ability to arrive at false conclusions. It therefore uses a strict
methodology and broad consensus to check all knowledge. Nevertheless,
this sort of knowledge is by definition provisional.
We recognise that our knowledge is ultimately subjective in the
sense that it is the result of a physical process. Our senses register
stimuli and our brain interprets and stores them. The process is unable
to render more than an approximation of what is "really out there".
Some kinds of knowledge are arrived at by our application of
reason alone - such as 2 + 2 = 4. The entire body of mathematics is
based on the notion that contradictory language isn't a valid expression
of reality .We don't class as "knowledge", for
example, the statement that "Square shapes are round". To do so would
render language and therefore mathematics utterly useless as a means of
Scepticism is useful and necessary, given the uncertainties we
face in knowing what "really is". Nevertheless we must in some sense
trust our experience. You are welcome to maintain that the brick you
dropped on your foot isn't real and that the pain is an illusion. I
prefer to infer that a brick dropped on my foot is likely to be real
enough to hurt like hell.
Relativism appears to be a dead-end epistemologically. It seems,
for example, that no religion can make absolute claims if this stance is
taken. Thus some would suggest that religion is a function of culture
and that none has the right to claim superiority in this respect. If I'm
born in Europe I'm likely to find Christianity more compelling than any
other religious system. If born in India, Hinduism might be more natural
 See Cartesianism
 Relativism in A Companion to the Philosophy of