IDEA FOUND // IDEA 111
Modus Ponens
“It is the most direct conditional step: the condition holds, so its consequence follows.”
01 / PLAINLY
What it means, plainly
Modus ponens follows this pattern: if A happens, B happens; A happens; therefore B happens. Classical logic treats the pattern as valid.
02 / CONTEXT
A little more
The form is: if A, then B; A; therefore B. In classical logic it is valid, provided the conditional and the assertion of A stand.
03 / WHY IT MATTERS
Why it matters
Spotting the pattern helps you follow instructions and explanations while keeping a correct logical step separate from a questionable starting claim.
04 / EXAMPLE
A familiar example
If the correct key turns, the door opens. The correct key turns. Therefore, the door opens.
05 / LIMIT
What it does not mean
The rule alone does not prove that the opening conditional accurately describes the world.
06 / NOTICE
Notice it in your day
Fill in this pattern with an everyday case: if A, then B; A; therefore B. Then ask what supports the first sentence.
FINAL NOTE
The idea worth keeping
Spot the form, but also audit the link between condition and consequence.
QUESTIONS / 02
Questions people still have
What is the form of modus ponens?
The complete form is: if A, then B; A occurs; therefore B occurs.
Does the rule prove that ‘if A, then B’ is true?
No. It shows what follows if that conditional and A are accepted.