What is Critical Thinking?
Most of us would agree that critical thinking is the mental process on
the basis of which we make reliable judgements on the credibility of a
claim or the desirability of a course of action. Members of a jury use
their critical faculty to scrutinize the evidence presented in court to
decide whether the accused is guilty or innocent. Members of a board of
directors use their critical faculty to decide whether a proposed reform
would be beneficial or harmful.
The above characterization of critical thinking contrasts with the narrow
view that equates critical thinking with the application of classical
deductive and inductive logic, and the use of the checklist of the logical
fallacies found in logic textbooks. Pedagogical approaches that incorporate
the logic-based view have two serious flaws. First, they give the misleading
impression that reasoning is the sole ingredient of critical thinking.
Other central ingredients of critical thinking, such as assessing the
credibility of the facts presented, looking for additional facts which
could be inconsistent with the proposed conclusion, looking for alternative
conclusions, choosing between alternative conclusions, and so on, hardly
ever figure in traditional treatments.
Second, even within reasoning, the traditional programme ignores the
types of formal and informal reasoning that lie outside the domain of
classical logic. Traditional logic covers only a small fragment of the
reasoning actually used in academic activities and everyday life. For
instance, most traditional books on critical thinking hardly mention the
central concepts of critical thinking needed for the assessment of conclusions
based on experimentation, such as sampling biases and standard deviation,
as such topics are found in textbooks on statistics rather than classical
Given the above view, let us ask: Can critical
thinking be taught? The answer depends on what we mean
by "teaching'. If "teach x critical thinking" means "make
x think critically", the answer is probably no. But if it means "help
x acquire the ability to think critically" or "help x improve
the ability to think critically", the answer is yes. If teachers
can help their students learn to paint, sing, dance or play chess, they
can also help students develop or improve the ability to think critically.
How can we teachers help our students develop
their critical thinking faculty? A standard response would
be: give the students one or two lectures on critical thinking. However,
I doubt very much if we can make any serious difference if a curriculum
devotes to critical thinking one or two lectures, or even a whole module,
but ignores it in remaining modules. Whether or not such specialized lectures
or modules are available, we need to incorporate critical thinking in
every module we teach.
Viewed from the broad perspective of the modes of assessing the credibility
of claims and the desirability of actions, we may distinguish between
global and discipline-bound critical abilities. When I critically read
a research paper in my area of specialization and make an assessment of
the claims made in the paper, I use my discipline-bound critical faculty,
which involve making use of the information, available in my discipline,
as well as the modes of thinking frequently employed in my discipline.
In contrast, when I critically read a newspaper article on an article
in Scientific American on a topic outside my discipline I use my global
critical faculty These two levels of critical think ing clearly interact
and reinforce each other.
From this vantage point, each module taught in a university has a role
to play in strengthening certain aspects of critical thinking. For instance,
a module in experimental psychology may tend to focus on the ability to
assess experiment design and statistical data, while a module in theoretical
chemistry may tend to focus on the ability to assess theoretical interpretations,
test predictions, look for alternative interpretations, and so on. Hopefully,
the combined effort from a number of disciplines will lead to the enhancement
of global critical thinking as well.
A frequently-voiced complaint among university teachers is that students
are unwilling, or even unable, to think critically. Assuming that this
feeling is not baseless, let us ask: Why is
critical thinking underdeveloped among students? The answer,
I think, can be stated as follows. An essential prerequisite for the development
of critical thinking among students is the critical understanding of what
they learn in their classes. The traditional framework of education that
most of us rely on does not have a provision for critical understanding,
and hence does not facilitate critical thinking.
By critical understanding I
mean the understanding that involves not only familiarity with the concepts
and propositions that we call knowledge, and the ability to apply them
to new situations, but also an awareness and appreciation of the evidence
for what is presented as knowledge. Textbooks and lectures typically present
the conclusions arrived at by the academic community, but they rarely
present the evidence that leads to these conclusions, or the arguments
that support them. In the absence of evidence and argumentation, students
are not in a position to critically evaluate the knowledge presented to
them. All they can do is accept on trust what is handed down to them,
a situation that is hardly conducive to the practice of critical thinking.
Let me explain. Most educated people in the twentieth century believe
that the earth rotates around its axis, and revolves around the sun. However,
very few people realize that these are not observable facts, but only
theoretical interpretations supported by considerable evidence. The only
way to observe the earth's revolution around the sun is to go outside
the solar system, for which space travel has not equipped us with yet.
There is no way to observe the earth's rotation, unless we go outside
the universe to observe the earth and the stars from an independent reference
point. When viewed from the earth, all we can see is a pattern of changes
in the location of the heavenly bodies: while the position of the star
called Polaris appears fixed, the rest of the stars describe a circular
motion around Polaris. This observed fact can in principle be explained
by assuming either that the earth rotates around its axis, or that the
sky rotates around the earth. Why then do we now accept the former hypothesis
rather than the latter one? The answer is that the assumption of the earth's
rotation (combined with a few other assumptions) allows us to calculate,
in a simpler manner, the observed changes in the locations of stars and
other heavenly bodies. Until we can find a better set of assumptions,
we must subscribe to the hypothesis of the earth's rotation.
Critical understanding entails raising the question (e.g., What is the
evidence that justifies the assumption of the earth's rotation?) and being
able to make an assessment of the evidence. For students to become aware
of such questions of evidence and to assess the evidence relevant to conclusions,
it is important that textbooks and teachers help them become aware of
this dimension of human knowledge. By and large, traditional education
does not deal with questions like:
- What is the evidence to assume that human beings evolved from monocellular
- What is the evidence to assume that oxygen has a valency of two?
- Why should we assume that there are such things as electrons, and
that they are negatively charged?
- Why should we assume that there is such a thing as social class?
For instance, chemistry textbooks tell students that a molecule of water
consists of two atoms of hydrogen and one atom of oxygen, but they generally
do not discuss the facts and arguments that support this conclusion, let
alone discuss Dalton's idea that one atom of hydrogen combines with one
atom of oxygen. As a result, students get into the habit of uncritically
accepting as facts the theoretical assumptions presented to them in their
textbooks and lectures. By leaving out critical understanding from the
curriculum, the traditional framework of education pre-empts the possibility
of critical thinking.
As long as textbooks and lectures fail to deal with evidence, alternative
conclusions and argumentation, it would be unrealistic to expect students
to develop critical thinking. The first step towards the teaching of critical
thinking is therefore bringing into our syllabuses, lectures and examination
questions, not only the conclusions accepted in the academic community,
but also the evidence and argumentation that demonstrate the credibility
or lack of credibility of these conclusions and their alternatives.