Certainty
Certainty is a lack of doubt about
some state of affairs. For example, if I have no doubt that the earth is the
third planet from the sun, then I can be said to be certain of that fact.
Certainty admits of degrees, just as doubt admits of degrees. Absolute
certainty is the lack of any doubt at all. Short of that, there are various
levels of relative certainty.
Philosophers have sometimes distinguished between psychological certainty, which I have described above, and another kind of certainty that is called epistemic, logical, or propositional. There is no universally accepted definition of this second kind of certainty, but it usually has something to do with the justification or warrant for believing a proposition: a proposition is epistemically certain if it has, let us say, a maximal warrant. The nature of a maximal warrant is defined differently in different epistemological systems. Descartes thought that propositions, to be certain, must be warranted such as to exclude all grounds for doubt. For Chisholm, a proposition is epistemically certain if no proposition has greater warrant than it does. And different philosophers give different weight to logic, sense experience, intuition, etc. in determining what constitutes adequate warrant.
In my judgment, epistemic
certainty, however it be defined, is not something sharply different from
psychological certainty. Whatever level of warrant is required for epistemic
certainty, it must be a level that gives us psychological confidence. Indeed,
if we are to accept some technical definition of warrant, we also must have
psychological confidence that that definition actually represents what we call
certainty. So it may be said that epistemic certainty is reducible to
psychological certainty. But it is also true that we should try to conform our
psychological feelings of certainty to objective principles of knowledge, so
that our doubts and feelings of certainty are reasonable, rather than arbitrary
or pathological. So perhaps it is best to say that psychological and epistemic
certainty are mutually dependent. In Frame, Doctrine of the Knowledge of God,
I have tried to describe and defend the mutual reducibility of feelings and
knowledge.
Philosophers have also differed as
to the extent to which certainty is possible, some being relatively skeptical,
others claiming certainty in some measure. Some have distinguished different
levels of knowledge and have relegated certainty to the higher levels. Plato,
for example, in the Republic, distinguished between conjecture, belief,
understanding, and direct intuition, conjecture being the most uncertain, and
direct intuition (a pure knowledge of the basic Forms of reality) warranting
absolute certainty.
Is it possible to be absolutely
certain about anything? Ancient and modern skeptics have said no. According to
Descartes, however, we cannot doubt that we are thinking, and, from the
proposition ‘I think,’ he derived a number of other propositions that he
thought were certain: our existence, the existence of God, and so on.
Empiricists, such as Locke and Hume, have argued that we cannot be mistaken
about the basic contents of our own minds, about the way things appear
to us. But in their view our knowledge of the world beyond our minds is never
certain, never more than probable. Kant added that we can also be certain of
those propositions that describe the necessary conditions for knowledge itself.
And Thomas Reid and G. E. Moore argued that certain deliverances of common
sense are beyond doubt, because they are in some sense the foundation of
knowledge, better known than any principles by which they can be challenged.
Ludwig Wittgenstein distinguished
between merely theoretical doubt and real, practical doubt. In everyday life,
when we doubt something, there is a way of resolving that doubt. For example,
when we doubt how much money we have in a checking account, we may resolve that
doubt by looking at a check register or bank statement. But theoretical, or
philosophical doubts are doubts for which there is no standard means of
resolution. What would it be like, Wittgenstein asks, to doubt that I have two
hands, and then to try to relieve that doubt? Similarly for doubts as to
whether the world has existed more than five minutes, or whether other people
have minds.
The language of doubt and
certainty, Wittgenstein argues, belongs to the context of practical life. When
it is removed from that context, it is no longer meaningful, for meaning, to
Wittgenstein, is the use of words in their ordinary, practical contexts, in
what he calls their language game. To raise such philosophical questions is to
question our whole way of life. Thus for
Wittgenstein, relative certainty is possible in ordinary life through standard
methods. But the traditional philosophical questions are not proper subjects
either of doubt or of certainty.
So in the context of ordinary life
Wittgenstein allows for certainty of a relative kind. His argument evidently
excludes absolute certainty; but he does recognize some beliefs of ours (e.g.
that the universe has existed for more than five minutes) about which there can
be no doubt. He excludes doubt, not by proposing an extraordinary way to know
such matters, but rather by removing such questions from the language game in
which doubt and certainty have meaning.
But philosophy is also a language
game, and doubts about the reality of the experienced world have troubled
people for many centuries. Philosophers have not hesitated to propose ways of
resolving those doubts. So it may be arbitrary to restrict the meanings of doubt
and certainty to the realm of the practical, even given the possibility
of a sharp distinction between theoretical and practical. At least it is
difficult to distinguish between questions that are improper in Wittgenstein’s
sense and questions that are merely difficult to answer.
So the questions concerning
certainty remain open among secular philosophers. Since Wittgenstein, these
questions have been raised in terms of foundationalism, the view that all human
knowledge is based on certain ‘basic’ propositions. Descartes is the chief
example of classical foundationalism, because of his view that the basic
propositions are absolutely certain. Many recent thinkers have rejected
foundationalism in this sense, but Alvin Plantinga and others have developed a
revised foundationalism in which the basic propositions are defeasible, capable
of being refuted by additional knowledge. In general, then, the philosophical
trend today is opposed to the idea of absolute certainty; and that
opposition is rampant among deconstructionists and postmodernists.
The question also arises in the
religious context: can we know God with certainty? The Bible often tells us
that Christians can, should, and do know God and the truths of revelation
(Matt. 9:6, 11:27, 13:11, John 7:17, 8:32, 10:4-5, 14:17, 17:3, many other
passages). Such passages present this knowledge, not as something tentative,
but as a firm basis for life and hope.
Scripture uses the language of
certainty more sparingly, but that is also present. Luke wants his
correspondent Theophilus to know the ‘certainty’ (asphaleia) of the
things he has been taught (Luke 1:4) and the ‘proofs’ (tekmeria) by
which Jesus showed himself alive after his death (Acts 1:3). The centurion at
the cross says ‘Certainly (ontos) this man was innocent’ (Luke 23:47,
ESV).
The letter to the Hebrews says that
God made a promise to Abraham, swearing by himself, for there was no one
greater (6:13). So God both made a promise and confirmed it with an oath, ‘two
unchangeable things, in which it is impossible for God to lie’ (verse 18). This
is ‘a sure and steadfast anchor of the soul’ (verse 19). Similarly Paul (2 Tim.
3:16-17) and Peter (2 Pet. 1:19-21) speak of Scripture as God’s own words,
which provide sure guidance in a world where false teaching abounds. God’s
special revelation is certain, and we ought to be certain about it.
On the other hand, the Bible
presents doubt largely negatively. It is a spiritual impediment, an obstacle to
doing God’s work (Matt. 14:31, 21:21, 28:17, Acts 10:20, 11:12, Rom. 14:23, 1
Tim. 2:8, Jas. 1:6). In Matt. 14:31 and Rom. 14:23, it is the opposite of faith
and therefore a sin. Of course, this sin, like other sins, may remain with us
through our earthly life. But we should not be complacent about it. Just as the
ideal for the Christian life is perfect holiness, the ideal for the Christian
mind is absolute certainty about God’s revelation.
We should not conclude that doubt
is always sinful. Matt. 14:31 and Rom. 14:23 (and indeed the others I have
listed) speak of doubt in the face of clear special revelation. To doubt what
God has clearly spoken to us is wrong. But in other situations, it is not wrong
to doubt. In many cases, in fact, it is wrong for us to claim knowledge, much
less certainty. Indeed, often the best course is to admit our ignorance (Deut.
29:29, Rom. 11:33-36). Paul is not wrong to express uncertainty about the
number of people he baptized (1 Cor. 1:16). Indeed, James tells us, we are
always ignorant of the future to some extent and we ought not to pretend we
know more about it than we do (James 4:13-16). Job’s friends were wrong to
think that they knew the reasons for his torment, and Job himself had to be
humbled as God reminded him of his ignorance (Job 38-42).
So Christian epistemologist Esther
Meek points out that the process of knowing through our earthly lives is a
quest: following clues, noticing patterns, making commitments, respecting
honest doubt. In much of life, she says, confidence, not certainty, should be our
goal.
But I have said that absolute
certainty is the appropriate (if ideal) response to God’s special revelation.
How can that be, given our finitude and fallibility? How is that possible when
we consider the skepticism that pervades secular thought? How is it humanly
possible to know anything with certainty?
First, it is impossible to exclude
absolute certainty in all cases. Any argument purporting to show that there is
no such certainty must admit that it is itself uncertain. Further, any such
argument must presuppose that argument itself is a means of finding truth. If
someone uses an argument to test the certainty of propositions, he is claiming
certainty at least for that argument. And he is claiming that by such an
argument he can test the legitimacy of claims to certainty. But such a test of
certainty, a would-be criterion of certainty, must itself be certain. And an
argument that would test absolute certainty must itself be absolutely certain.
In Christian epistemology, God’s
word is the ultimate criterion of certainty. What God says must be true,
for, as the letter to the Hebrews says, it is impossible for God to lie (Heb.
6:18, compare Tit. 1:2, 1 John 2:27). His Word is Truth (John 17:17, compare
Ps. 33:4, 119:160). So God’s word is the criterion by which we can measure all
other sources of knowledge.
When God promised Abraham a
multitude of descendants and an inheritance in the
Thus Abraham stands in contrast to
Eve who, in Gen. 3:6, allowed the evidence of her eyes to take precedence over
the command of God. He is one of the heroes of the faith who, according to Heb.
11, ‘died in faith, not having received the things promised, but having seen
them and greeted them from afar…’ (verse 13). They had God’s promise, and that
was enough to motivate them to endure terrible sufferings and deprivations
through their earthly lives.
I would conclude that it is the
responsibility of the Christian to regard God’s word as absolutely certain, and
to make that word the criterion of all other sources of knowledge. Our
certainty of the truth of God comes ultimately, not through rational
demonstration or empirical verification, useful as these may often be, but from
the authority of God’s own word.
God’s word does testify to itself,
often, by means of human testimony and historical evidence: the ‘proofs’ of
Acts 1:3, the centurion’s witness in Luke 23:47, the many witnesses to the
resurrection of Jesus in 1 Cor. 15:1-11. But we should never forget that these
evidences come to us with God’s own authority. In 1 Cor. 15, Paul asks the
church to believe the evidence because it is part of the authoritative
apostolic preaching: ‘so we preach and so you believed’ (verse 11; compare
verses 1-3).
But how does that word give us
psychological certainty? People sometimes make great intellectual and emotional
exertions, trying to force themselves to believe the Bible. But we cannot make
ourselves believe. Certainty comes upon us by an act of God, through the
testimony of his Spirit (1 Cor. 2:4, 9-16, 1 Thess. 1:5, 2 Thess. 2:14). The
Spirit’s witness often accompanies a human process of reasoning. Scripture
never rebukes people who honestly seek to think through the questions of faith.
But unless our reason is empowered by the Spirit, it will not give full
assurance.
So certainty comes ultimately
through God’s word and Spirit. The Lord calls us to build our life and thought
on the certainties of his word, that we ‘will not walk in darkness, but have
the light of life’ (John 8:12). The process of building, furthermore, is not only
academic, but ethical and spiritual. It is those who are willing to do God’s
will that know the truth of Jesus’ words (John 7:17), and those that love their
neighbors who are able to know as they ought to know (1 Cor. 8:1-3).
Secular philosophy rejects absolute
certainty, then, because absolute certainty is essentially supernatural, and
because the secularist is unwilling to accept a supernatural foundation for
knowledge. But the Christian regards God’s word as the ultimate criterion of
truth and falsity, right and wrong, and therefore as the standard of certainty.
Insofar as we consistently hold the Bible as our standard of certainty, we may
and must regard it as itself absolutely certain. So in God’s revelation, the
Christian has a wonderful treasure, one that saves the soul from sin and the
mind from skepticism.
Bibliography
J. M. Frame, Doctrine of the Knowledge of God (Phillipsburg, N. J.: 1987).
E. L. Meek, Longing to Know: the
Philosophy of Knowledge for Ordinary People (
A. Plantinga, Warranted Christian Belief (N. Y.: 2000). A profound Christian reflection on the nature of knowledge and its warrant.
L. Wittgenstein, On Certainty (N. Y., 1972).
W. J. Wood, Epistemology (Downers Grove, 1998). Christian philosopher shows how knowledge is related to virtues and to the emotions.