Causality - What makes things happen?

Causality 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.

We say 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 this up???

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.  


People are 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 this. 


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 something happening.


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. can lead to developing new technology that improves our quality of life.

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 probable effect.

Third, and last, there is a fallacy that often emerges, when people consider cause and effect, one that leads them to making unrealistic decisions (see below).

 What is a Necessary Cause?

Basically, 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 Sufficient Cause?

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).

What 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." 

 These are rare.  Most causes are either necessary, or sufficient but not both at the same time.

A gene 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 concluding that...

...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.

"Studies show 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 else.

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.

 To read our article about the factors leading to (i.e., causing) success

 To return to the Articles Page

All written text on this website copyright Reality Check Online