Sunday, 4 December 2016

People And Logic

"Not that I have an infinite faith in logic to predict how people operate."
-SM Stirling, On The Oceans Of Eternity (New York, 2000), Chapter Nineteen, p. 393.

This is not just because people behave illogically. To think logically is to reason validly from premises - whether the premises are true or false. Thus:

A is a weak-willed alcoholic;
such a person will accept a drink if offered;
therefore, A will accept a drink if offered.

B is a strong-willed teetotaller;
such a person will refuse a drink if offered;
therefore, B will refuse a drink if offered.

Both these syllogisms are valid. But the premises may or may not be true. Might B lose his strong will under pressure? Might A gain some stronger motivation, e.g., from a religious conversion? We do not know all that goes on inside another human being. Therefore, we cannot predict anyone's actions with certainty.


  1. Kaor, Paul!

    Exactly! Your last paragraph expressed more clearly than I would probably put it how logical thinking cannot always correctly guide us in how people will behave.


  2. Generally speaking, logic is a tool. People operate from essentially instinctual and emotional drives, which supply motivation; logic is a means of getting what you want.

    1. Dear Mr. Stirling,

      I have to agree. Most of us are not in the least as coldly rational and logical as Mr. Spock. Logic helps us to obtain what we want, not why we want it.


    2. Sean,
      I think that the image of Spock misrepresents logic, though. Logic is, most basically, the kind of consistency between propositions without which we would not succeed in saying anything. Everyone accepts that, if they contradict themselves on a matter of fact, then they need to correct the contradiction. Thus, we all accept logic, usually without recognizing it as such.