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Joined 1 year ago
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Cake day: June 26th, 2023

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  • I’m not sure but could it be because, in your first truth table, you assumed the truth value of (a OR b) -> c to be true and you are finding the truth values of c that correspond with pairs of values of a and b?

    However, in the second table you are finding the truth values of ~(a OR b) OR c that correspond with truth values of c as well as a and b so just like you said, you cannot compare the two tables you present above.

    To get the truth table for the proposition (a OR b) -> c, you would find the corresponding truth values to those of a, b and c (like you did in the first table). Something like this:

    A B C   A OR B   (A OR B) -> C
    000       0             1
    001       0             1
    010       1             0
    011       1             1
    100       1             0
    101       1             1
    110       1             0
    111       1             1
    

    since it’s possible for the conditional proposition to be false (i.e. if either A or B are true yet C is false)