Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

HM interesting

  1. Apr 30, 2004 #1

    What would you make of the following statement:

    If the following statement is true, then the preceding statement is false.

    Is the implication false??? True???
  2. jcsd
  3. May 1, 2004 #2
    With these conditional statements, there are few levels of undefined conditions.

    What if: If the following statement is true happens to be false, then is the preceding statement false or true? So the following statement is defined as an indefined quantity. Otherwise, your conditional statement seems true to me.

    In terms of linguisitcs of your statement... it is rather strange.
  4. May 5, 2004 #3


    User Avatar
    Gold Member

    how should we interpret this sentence as one conditional statement or as two statements?
  5. May 5, 2004 #4
    You said it yourself - this is just one statement. There is no following or preceeding statement here, and if there were, then threre is no problem (in general) that one of them is false and the other true. Now, if you rephrased it somehow, then maybe you'd have a more problematic situation..
  6. May 6, 2004 #5
    Just thought of a way to rephrase that:

    The following statement is true.
    The previous statement is false.

    Now you have a contradiction. What's more, neither statement can be true, but also, neiter one can be false. This is problematic... :confused: Quantum logic anyone (true-false superposition)? :wink:

    EDIT: A simpler version: This statement is false.
    Last edited: May 6, 2004
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook