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Comment by jameshart

17 days ago

The original article feeds precisely this misreading. It quotes the old IBM adage ‘a computer MUST never make management decisions’ (my emphasis) but describes it in its headline as ‘a computer CAN not make decisions’ (my emphasis)

These are not the same, and this misinterpretation of the author’s intent inevitably follows.

CAN NOT is horribly ambiguous in English which is why RFCs use MUST and MAY.

In casual speech someone might say “you can’t park there” but that’s not true. They might mean “you must not park there” or “you should not park there” but the only reason they are telling you is because you CAN park there.

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jameshart

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Kevin_Flynn  17 days ago

> CAN NOT is horribly ambiguous in English which is why RFCs use MUST and MAY.

Is it ?

I thought 'can' denotes a possibility, while 'not' negatates it ?

  • jameshart  17 days ago

    It gets used more often to express prohibition not impossibility (“you can’t be in here” spoken to someone who manifestly is for example). Also disbelief (“this can’t be happening” about something that is happening). It’s just not clear which sense people mean it in, so it can’t be used when you want to be sure you can’t be misunderstood.

    For another example of ambiguity, consider the sentence “A triangle can not have any obtuse angles”.

    Is this 1) true, because there exist triangles with only acute angles, or 2) false, because triangles can have obtuse angles?