Causality - What makes things happen?
is often an important part of our understanding of how the world
works. It is a key aspect of our view of reality, and how
we go about predicting, or creating the future.
Those of you have already
read our article about Factors of Success know that hard work
alone is not a necessary and sufficient cause for success--here
is where we explain more about that.
that A causes B, A is the cause, and B is the effect. These are two events that occur in time,
with A always preceding B, and with B seen as resulting from A.
Another way of putting it is, "If A, then B."
Humans recognize patterns, including those that happen and
repeat over time (temporal patterns).
So...why do we bring
For several reasons.
First of all, everyone, at one time or
another, looks for causes and effects. When we
try to figure out the whys and wherefores, were looking at
causes and effects. We do this to understand things that
happen, including things we want to happen.
often concerned with cause and effect, when they set out to do
something. Their goal is the effect, and they seek to find
what causes, or actions on their part, will lead to the the
effect they seek (their goal).
And people often look to
understand the behavior of others, as well as why things happen
in the world at large. Humans are particularly adept at
Possibility and Probability: In the process of examining
causes and effects, both possibility and probability are taken
into account. The latter is especially relevant in
correlational studies where multiple causes may contribute to
Prediction and Quality of
Life: Scientists are particularly
concerned with this, as they try to figure out the causes and
events that occur in the world. If they do so correctly,
it can lead to predicting what will happen. AND...it can
lead to developing new technology that improves our quality of
Second, when it comes to
reality, it can get complicated, so much so that folks don't
realize that it doesn't make sense to seek, or expect simple
causes for things. And that's because there are different
kinds of causes. These causes relate what is possible for
an effect to occur, as well as what sorts of causes can lead to
Third, and last, there is a
fallacy that often emerges, when people consider cause and
effect, one that leads them to making unrealistic decisions.
is a Necessary Cause?
this means that A must be present for B to occur. If A is a
necessary cause of B, then the presence of B necessarily implies
the presence of A; however, the reverse is not true by default.
The presence of A alone does not imply that B will occur.
Another way of looking at it is in terms of possibility; a
necessary cause is one that makes something possible.
Oxygen must be
present for fire; however, the fact a room contains oxygen does
not automatically imply that there is also a fire in the room.
Oxygen is a necessary cause for fire. It makes it possible
to ignite something.
What is a
If A is a sufficient cause of B, then the presence of A
necessarily implies the presence of B. However, another
cause C may alternatively cause B. Thus the presence of B does
not imply the presence of A. A sufficient cause creates
the probability something can happen, but
Matches can be a
sufficient cause for igniting a fire, but so can others things,
like a short circuit, lightning, or a magnifying glass to focus
sunlight. So if there is a fire,
that does not necessarily mean there are also matches. The
level of probability can vary from one sufficient cause to
another (e.g., a lit match is a more probable cause for ignition
than a magnifying glass focusing sunlight, since the former is
more available and easier to use than the latter).
is a Necessary AND Sufficient cause?
Now, as it
happens there are causes that are both necessary and sufficient,
in which case presence of cause A will always result in the
presence of effect B, and vice versa. In this case, we say
"B will occur if, and only if A occurs first."
rare. Most causes are either necessary, or sufficient but
not both at the same time.
mutation associated with Tay-Sachs is both necessary and
sufficient for the development of the disease, since everyone
with the mutation will eventually develop Tay-Sachs and no one
without the mutation will ever have it
A Causal Fallacy
(one that occurs far too often):
This occurs most often when
folks don't know the difference between sufficient and necessary
causes and instead lump them together, which leads them to
...If a cause turns out to
NOT be sufficient, it must also NOT be necessary.
Now that you know the
difference between these two types of causes, you know this is
absolutely not true. But you can and will hear this sort
of fallacy stated concerning all sorts of things.
that simply spending money will not improve test scores in
schools. So we should be looking at something else, like
better teachers, or higher levels or parental involvement."
We should note that the the
conclusions are often implicit (that is, unstated). If
spelled out, the conclusion is that we should stop doing one
thing and start doing something else. And while doing
additional things may be beneficial, that does not mean we have
to stop what was already being done.
But this misses the point.
In the example above, the problem may not be just spending
money, but what the situation is prior to spending money.
In other words, if not much money is being spent at all,
spending more might be beneficial. But if a lot is being
spent, then it may be a matter of what the money is spent
on--there may be areas that won't benefit from further spending,
but areas where increased spending will be beneficial. It
does not follow that since scores haven't improved after
spending money, we should stop spending money and do something
By the way and while we're
at it, this question about spending money is OFTEN missed
whenever people talk about government spending. Simply
looking at the amount being spent alone and then deciding that
more, or less needs to be spent based on the amount and the
current results is inappropriate. Further critical
thinking (discussed elsewhere on this web site) is called for.
At the very least, the amount being spent and on what should be
addressed prior to making any decision about further increases,
or decreases in spending.
Logic vs. Science
It might interest you to know
that there are those, usually logicians, who will tell you that
Necessary Causes and Sufficient Causes, aren't really causes.
For them, ONLY causes that are both Necessary AND Sufficient are really
causes. They prefer to call the others "Necessary
Conditions" and "Sufficient Conditions." It's their way of
saying that they are "conditional" causes, because they don't,
in themselves always explain what causes something to happen.
But this is mostly a matter of
semantics, one that scientists ignore, because they know and
routinely deal with the fact that there are multiple causes, and
thus do not look ONLY for Necessary AND Sufficient Causes.
In real life, causes can turn out to be rather complicated,
for example, looking something like this:
Fortunately for us all,
researchers have a whole bag of resources to deal with all this,
including data collection methods, and data analysis models.
read our article about the factors leading to (i.e., causing) success
return to the Articles Page