Tag Archives: René Descartes

How do you know you exist?

13 Jul

Penseur  The math whiz and philosopher, René Descartes, sought to clarify his doubt and his knowledge.  So he pushed back as far as he could to what he could know for sure.  Most people can quote part of his argument:

I think, therefore I am

As many of you know, he left out the major premise.  No ‘doubt’ that it resided in his mind, but seemed too obvious to mention.  That’s the nature of an enthymeme, an unspoken premise or conclusion.

For example:

Sally pipes up with enthusiasm: I invited our neighbors to join us this Saturday for a picnic in the park!

Sam responds sourly: Great, now we can count on it raining this Saturday!

What’s the unspoken premise?

  • It always rains when we plan a picnic in the park!

Back to Descartes and his implicit assumption supporting ‘I think, therefore I am’

It has to be: All creatures that think exist.  So the complete syllogism would look like this:

P1 – All who think are

P2 – I think

C – Therefore, I am

What brought to mind Descartes’ foundation for knowing or epistemological basis for knowledge was a different origin for the assurance of one’s existence.

While listening to a podcast, I heard an African Christian talk about what anchors him in life. He talked about community as being this source.  He explained:

  • Because the community is the primary building block of humanity, each of us derives his or her own sense of self

His enthymeme would go like this: We are, therefore I am!

And by fleshing it out with the implicit major premise, we have:

P1: If there is a communal unit, then individuals can fully have their being

P2: There is a community in which I a recognized member

C: Therefore, I exist as a full human being

Thinking about and contrasting Descartes’ individualistic enlightenment view with this African brother’s sense of himself as part of a larger group strengthened my growing view that it is not good for man or woman to be alone.  After all, the one true God is a community of 3-in-1, a Triune Happy Godhead.  And if we are made in His image, then to feel fully alive and to function with health, we need to anchor ourselves in community with other people.

I need not be intimidated by famous thinkers and learned philosophers.  The simplest of men and women often are the wisest.


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.