Tag Archives: Cold Case Murders

Logical Gal – Are you sure?

22 Apr


“You can’t be sure about anything!”

Beyond death and taxes, a lot of people maintain that position.  But is it so?

What is certainty and are there different kinds?

First a definition – Generally speaking, in every day language, certainty is the quality of being absolutely true.  What is ‘certain’ can be a fact that corresponds to reality or an event that definitely has taken place or will take place without a doubt.

Going deeper, one can differentiate between types of certainty.  We have

  • mathematical certainty – no one doubts that 2+2 make 4

Then there is

  • logical certainty – the world of deductive reasoning, portrayed by the simple syllogism.  Here we can be certain that a conclusion is true if the premises are true and the way of reasoning follows the rules (thus qualifying as ‘valid’)

Premise 1 – All humans die

Premise 2 – Joe is a human

Conclusion – Joe will die

The other day, I heard someone talk about a 3rd kind of certainty, that of

  • moral certainty I was intrigued by how he explained this branch of certainty.  From a sermon on Biblical hope here is what John Piper wrote/delivered:

“There is a kind of legitimate certainty and confidence that does not come from mathematical calculations or merely logical laws. I call it “moral certainty.”

Rooted in Acts of Will

I call it moral because it is rooted in the commitment of the will of persons. And the will is the seat of morality. That is, we can only speak of moral right and wrong in relationship to acts of will. So whatever has to do with the will is an issue of morality. And moral certainty is a certainty that is based on acts of will.”

René Descartes, French philosopher and mathematician described moral certainty this way -“certainty which is sufficient to regulate our behavior”, Link to article quoting him

Intrigued by the concept of certainty, I checked to see if there were other types of certainty.   After nosing around different websites, I learned that in a court of criminal  law, to come to a conviction the jury must agree ‘beyond a shadow of a doubt’ that the accused is guilty.  That is probabilistic certainty – knowledge that is most likely to be true. . In fact, examining cumulative circumstantial evidence to arrive at a high probability of guilt can often solve murder cases that are ‘cold’.

Of course, there are less-than-credible claims to certainty.  People talk about psychological or ideological certainty – a WANTING to believe something to be so, despite the facts. There is also the danger that in the broad category of ‘mathematical certainty’ modeling future outcomes might have some hidden assumptions that are not necessarily true.

At the end of the day, we should approach the concept of certainty with HUMILITY.  I’m not advocating a posture of skepticism, but the acknowledgement that we, as finite human beings, might not be right about everything.