Tag Archives: Skepticism

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.


Logical Gal and Evidence-Based Medicine – is there any other kind?

9 May

What a concept!  Relying on medical practices and prescribed treatments that actually work and have the evidence to back them up!

I recently listened to a conversation between Al Mohler and Candy Gunther Brown, PhD from Harvard.  The topic was fascinating!  Dr. Brown has studied the religious content of complementary and alternative medical practices such as chiropractic, yoga and reiki.

Audio talk + transcript entitled: “Are we all syncretists now…”  – about complementary and alternative medicine and evangelical Christians

The discussion focused on Dr. Brown’s research in her latest book Link to book at Amazon

What I found compelling as a logical gal was the distinction between medicine that could point to double blind trials to substantiate its claims and medicine that was NOT evidence-based.

Evidence-based medicine

Apparently many of those who practice these alternative ‘therapies’ know how to shift their language to suit their audience. This tailoring the vocabulary extends to efforts to appeal  to the public’s desire for something ‘scientificky’ and ‘natural‘ or appeasing Christians’ worries about Buddhist or Hindu influences by changing the names of movements.


Yoga in public schools

Dr. Brown was called as an expert witness in last summer’s California court case regarding the teaching of yoga in Encinitas public schools (San Diego area) . Even though she supplied substantial reasons why yoga is a religious practice, the court ruled otherwise. NPR report on ruling

Whether you are bothered by the question of religious content or not in these practices, you SHOULD BE concerned about any medical practice that is more quackery and wishful thinking.  Practice reasoned skepticism!!

Skepticism and truth


Logical Gal examines the ‘extraordinary’

28 Feb

Extraordinary Claims

I heard this thrown out as a defeater for the truth of the resurrection of Jesus.  At first blush, it sounds pretty reasonable.  But then the skeptic in me started to question this claim.

When you face an assertion such as this you need to ask about the quantifier.

To wit, do ALL extraordinary claims require this degree of evidence?  or just some?

If the one making this ‘claim’ affirms that he intends ALL such claims to require that caliber of evidence, then you have an easy way to defeat his proposition.  All you have to do is think of ONE counter-example and you have defeated him.

So what would qualify as a potential counter-example?  I immediately thought of the lottery.

Lottery winner

If one of our sons called up to tell us that he had won the lottery, that would qualify as an extraordinary claim.  So what kind of evidence would he need to produce for me to believe him?

Actually, something very simple

  • He could show me the winning ticket
  • I’d also take a picture like the one above as proof

It wouldn’t take much to substantiate his amazing claim.

Now back to the context of the Carl Sagan quote.  Sagan who was paraphrasing David Hume was referring to the resurrection of Jesus from the dead.  That certainly does qualify as an extra-ordinary claim.  You don’t see former dead people walking around very often.  So how would I handle the demand for ‘extra-ordinary’ evidence?

What do we do when we don’t know which way to proceed?

Ask questions

The easiest tact to take is to ask your interlocutor what she means by extra-ordinary evidence. What would qualify?  After all, we have eye-witness testimony that was verifiable by many.  Paul mentions that over 500 people encountered the risen Jesus.  And when Paul made that claim, had it not been true, most of those people were still alive themselves.  They could have come forward and said, “I did not say that!”  Moreover, no body was ever found (that would have defeated the ‘resurrected Jesus’ claim) and scared followers changed their demeanor overnight and started a movement that has only built up momentum in the 2000 years since the event.  Christianity continues to expand today.

Finally – I would ask Carl Sagan or David Hume or anyone who repeats this double extra-ordinary assertion the following: Is YOUR proposition an ordinary one or an extraordinary one?  What kind of evidence do YOU have to justify your position?

We logical Joes and Janes have to exercise healthy skepticism.  Resurrection-deniers don’t have a corner on that market!