Cultivating Critical Thinking Skills
How are your thinking skills? Are you a critical thinker?
Or are you a poor thinker, a sloppy thinker, or a rationalizing
thinker? Fortunately, poor and sloppy thinking can be corrected
more easily than the last. Many very intelligent people seek
only to use their thinking to prove what they already believe
to be true.
That latter approach is not any part of critical thought.
Depending on which psychologist, philosopher, or brain scientist
you ask, critical thinking has many definitions, but all of them
seem to agree that it includes challenging and analyzing our
own motivations, thought processes and conclusions.
What else? Let's start with a basic definition:
"Rational and reflective thinking focused on deciding
what to believe and/or how to act."
Rational is not to be confused with logical. Many of the most
irrational ideas and actions proceed logically from a chosen
set of premises. If you start with certain premises, like a flat
Earth, it can be perfectly logical to assume a boat will fall
off the edge if it goes too far. Logic simply works from premises
to arrive at conclusions systematically, but the premises themselves
may be right, wrong, or imperfect.
Rational thought takes into account the possibility that there
is not a perfect correspondence between our premises and reality.
It starts with observation, evidence gathering, and inductive
reasoning. Logic is limited to deductive reasoning, and one bad
premise makes all deductions suspect and possibly false. So critical
thinking is rational, but challenges that which is simply logical.
Critical thinking is reflective, asking questions like, "Where
could I be wrong here? What assumptions am I making and are they
justified? What other explanations are there?
For example, suppose on a hot humid day, you think to yourself,
"Humidity makes the air feel warmer, and it is normally
more humid in Michigan than in Arizona, so if the temperature
is the same in both places, it will normally feel warmer in Michigan."
The logic is unassailable, but the conclusion is wrong, as I
and anyone who has lived in both places in winter can attest
to. Humidity actually makes it feel warmer when it is warm and
colder when it is cold.
How do you avoid errors like this? You ask if it's true
that humidity makes air feel warmer. The experience of a hot
day says yes, but because you look for possible errors
you note the hidden assumption that "this is always true
at any temperature." Because you challenge assumptions,
you remember that the hot feeling is in part because your sweat
can't evaporate as fast when it is humid, so your body's ability
to cool itself is limited. Upon reflection, you realize this
wouldn't matter as much when it's cold, because you don't sweat
In this case, you might already know enough to see the error
and come to a different conclusion. If not, a bit of critical
thought would at least point out the need to gather more information
and evidence. This example gives you some idea of the mind set
of a critical thinker, but what else can you do to develop critical
thinking skills? Some suggestions follow.
Ask for Evidence
Get in the habit of asking for evidence when someone makes
a claim. This can be as simple as asking "where did you
read that?" or "Was that speculation, or did they test
it?" You should also be prepared to provide evidence for
your own claims. None of us carries our sources with us, of course,
but you should be able to get a sense whether there really is
some basis for a claim.
Consider the Source
Since people don't carry evidence around with them, we accept
many things said, at least for the sake of argument (otherwise
our conversations would be very short, and more like interrogations).
But we can consider the sources of the information. Does this
person usually remember the facts correctly, and is the source
they refer to reliable? Make it a habit to ask yourself these
Motivations determine what we believe, what others believe,
and what evidence is considered by all of us. Thus, some newspapers
and magazines can be entirely slanted in their view, but be motivated
to have all of their facts correct. Critical thinking requires
that we ask why they have selected these facts to report, and
what facts they are leaving out. We should of course ask if there
is enough of a motivation for simple dishonesty as well.
Habitually reflect on the premises of a claim or argument,
whether another's or your own. Actively try to spot weaknesses
in them. Remember that one bad premise can taint all that comes
Be Open to Changing Your Mind
Try to always be ready and willing to change your mind based
on new evidence. In the sciences, critical thinking is crucial,
and a good scientist is ready and willing to drop the beliefs
of a lifetime if better ones present themselves. Make it a point
to ask yourself what evidence would change your mind. This prepares
you for the possibility.
Consider Your Own Experience
I heard someone make a claim that is "politically correct"
the other day. As is common with such claims, it is assumed that
everyone agrees. But just a moments reflection made me realize
that my own experience refuted the claim. Compare what is said
to your own knowledge and experience.
Look for Common Logical Fallacies
Try to habitually identify common logical fallacies and errors.
For example, if you ever hear an argument based on what some
"expert" or "authority" said, immediately
dismiss it. The claim may be true, but look for other ways to
verify it. An "appeal to authority" is a logical fallacy
based on the hidden assumption that "If he said it, it must
be true." Respect for an authority may suggest a closer
look at the evidence, but should not be considered strong evidence
by itself. Watch for this and other logical errors.
Critical thinking requires us to confess our ignorance, at
least to ourselves. A common response to not understanding something
is to invent an explanation (this is the whole basis for most
claims of "psychic powers"). A better way is to habitually
say, "Hmm... I don't know. I'm not sure. I'll wait for more
information or evidence." Speculation has its place, but
when speculation becomes explanation, it stops the search for
truth and prevents the truth from even being seen when it becomes
Look for Alternative Explanations
You mind should be thinking like this: "Hmm... I can
see that this explanation makes sense, but what other explanations
are possible?" Of course, when other possibilities do present
themselves, you should then be willing to look at the evidence
for these. This is how you develop your critical thinking ability.