2.2f: Conditional Symbolizations in SL

Use the following symbolization key to symbolize 1 - 5 in the space provided. Type the "horseshoe" with the '>' key.

F: There is fire.
O: Oxygen is present.

  1. If oxygen is present, then there is fire.   (note: this sentence is often false because fire does not always result when there is oxygen! but you can still symbolize it.)

    Note: You can't just switch antecedent and consequent in the symbolization of 1. That is fallacy! (What is the name of this fallacy?)

  2. If there is fire, then oxygen is present.   (note: this one is true)

    This is a fact about combustion: Oxygen is a necessary condition (i.e., a requirement) for fire.

  3. There is fire only if oxygen is present.   (note: this one is logically equivalent to 2)

    It's good to see that this one -- like all of these -- has more than one logically equivalent and correct answer.

  4. There is fire if oxygen is present.   (note: this one is just like 1!)

    This one is just a "stylistic variant" of number 1. We symbolize it the same way. The "if" clause is the antecedent.

  5. Oxygen is present if and only if there is fire. (note: this one is also often false)

    Now, think about the main connective...it's the last connective used in the builiding process. AND think about a shorter way to do this one.




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