False  Positive and False Negative: Part III

So now you know what they are.  And we've looked at how to apply these two to the matter of reality (when we try to see reality, we can see things correctly, or incorrectly).  What we see can be true, or false (we're still leaving out the idea of intentional falsehood, or lying--what the boy who cried wolf did). 

Rain, rain, go away...

Now, this is where it can get a little complicated, so consider the following: We look out the window to see if it's raining, and we either see that it is, or that it isn't.

So...is it really raining?  Is it really not raining.  Our answer can be either yes (a positive), or no (a negative).  Now if we correctly see reality, the yes, or the no may be true.  But maybe we don't see reality correctly (maybe there's a sprinkler outside making it look like it's raining, when it's not).

So here's what this all looks like

Harold and Robert Revisited

Here's the same chart applied to our story about Robert and Harold.  If we test someone for cancer, and the results reveal they have cancer,  that can be true (the person really dose have cancer), or false (the person really doesn't have cancer).  And if the results show no cancer, that, too, can be true (there really is no cancer) or false (there really is cancer.   Here's a visual picture of what we're talking about:

Seeing may be believing, but sometimes, in spite of our best efforts, we can be wrong.  The fact is, we can think, or believe we see reality correctly, when we don't.  Why?  It can result from many different things.  So we try to prevent it from happening.  In Science (with a capital "S"), we have a method that we've developed to help prevent seeing things wrong.  This method attempts to provide valid results.  It includes things like making sure data is clearly visible and can be replicated.

So we have to deal with that, too.  BUT, and this is a big but, when we try to reduce the possibility of one kind of false conclusion, we increase the possibility of the other.  Why?  Because how we do this is by how high, or low we set the bar for deciding our conclusion (deciding whether our observations, test results, etc. are true, or false).

In each case, we have to decide which of these two errors we can best tolerate, the false positive, or the false negative, knowing that when we increase to possibility of the one we prefer, we reduce the possibility of the other.  If, in the case of convicting someone of murder, we don't want to put an innocent person to death, we increase the possibility of setting a murderer free.  That's just how it is.

 To read about a couple ways of thinking (divergent and convergent)

 To read about causality

 To read about who likes it when people are ignorant, or stupid

 To go to the Articles Page.