Monthly Archives: July 2015

Isaac Watts – The Value of Logic #1

Why learn logic?

watts[1]The first is, the depth and difficulty of many truths, and the weakness of our reason to see far into things at once, and penetrate to the bottom of them. It was a saying among the ancients, Veritas in puteo, Truth lies in a well; and, to carry on this metaphor, we may very justly say, that logic does, as it were, supply us with steps whereby we may go down to reach the water: or it frames the links of a chain, whereby we may draw the water up from the bottom.

The Squirrel & the Rabbit: A Cautionary Tale

Poetics, Rhetoric

One late fall in the forest, a squirrel was running back and forth on the tree branches, storing up his nuts in the hollow of an old oak near his home. He was careful to keep his storage place secret so that the nuts would not be stolen, and to make the place deep and high in the strong tree. As he was busy storing the product of his labors, he ran across a rabbit returning from one of his visits to a nearby farmer’s garden. The rabbit had lots of carrots that he kept in some tall grass outside his rabbit hole. The squirrel saw this and called down to the rabbit, “Friend, shouldn’t you put that produce in a safe place? Anyone or anything could take them from you, and all your labor will be in vain!” The rabbit replied, “Thank you for your advice, but I have been keeping my carrots in this grass for a long time, and nothing has ever happened to them.” But the very next day, when the rabbit was once again gone to the garden, a rat came scuttling by, saw all the delicious carrots, and carried off as many as he could to his home in the farmer’s shed. When the rabbit returned and saw the carrots gone from the grassy place, he ran all over in a panic trying to find where they all went, but to no avail. The squirrel came to him and said, “Friend, if you had listened to me and taken a little extra effort to keep the product of your work in a safe place, you would not be enduring this sad loss.” So you also should back up your computer files, for you never know what might happen to make you lose all your work.

#6 – On Mistakes

Commonplaces

“The man who makes no mistakes does not usually make anything.” – E. J. Phelps

“I don’t know the key to success, but the key to failure is to try to please everybody.” – Bill Cosby

“Avoid using mixed metaphors. They kindle a flood of confusion in your readers.” – Richard Lederer

Abraham and True Consequents

Uncategorized

In an earlier post, I gave an example of a scriptural argument which helps to show that a conditional with a false antecedent should be considered true. I recently ran across a biblical argument showing that, as in the defining truth table, a conditional with a true consequent should also be considered true. In Genesis 24:41, Abraham’s servant reports,

“Then you will be free from my oath, when you come to my clan. And if they will not give her to you, you will be free from my oath.”

The conditional is not necessarily meant to follow from the previous statement, but if it does, then this lends credence to the modern understanding of conditionals that when the consequent is true, the conditional itself must be true.

Jesus and false antecedents

Intermediate Logic,

Since the Stoics first considered the truth value of conditional statements, there has been debate over whether a conditional with a false antecedent should be considered true, as modern propositional logic holds. Let me nudge the discussion forward by considering Jesus’ response to Pilate during His trial:

Jesus answered, “My kingdom is not of this world. If My kingdom were of this world, My servants would fight” (John 18:36)

Jesus speaks truth. Thus the statement “My kingdom is of this world” is false, being the negation of his first statement. But this false statement is the antecedent of the true conditional, “If My kingdom were of this world, My servants would fight.” 

Nudge.