Lesson 10 of Introductory Logic discusses the possibility that two statements delivered by different people may seem to be inconsistent, but upon further examination turn out to actually be consistent. We can call these seeming disagreements, and they can happen in one of two ways. Continue reading A Seeming Disagreement
I recently had the pleasure of listening to Andrew Pudewa, the director of the Institute for Excellence in Writing and a father of seven, speak at an education conference on the importance of reading aloud to your children. As he spoke, I recalled with delight the many hours I spent reading to my four children before they went to sleep. My eldest is about seven years older than the youngest. I would first read the Bible, making sure I at least turned the page every night. We read it all the way through, Genesis to Revelation, over and over again (once we finished it in an airport), occasionally changing the translation. We would pray and sometimes sing, and then I would read a story, alternating each night between the boys’ room and the girls’ room (I tried to keep track by which room my chair was left in, only later learning that my girls would move my chair to the boys’ room during the day so that I would move it back to their room so they could be in their own beds as I read).
I am thankful that I kept a record of the books I read to them. I have listed them below, for anyone who might somehow benefit from knowing the stories that shaped my children (and me). They are listed roughly in the order that I first read them over the years. The underlined books are favorites that I read more than once. No doubt some books went unrecorded (I’m pretty sure I read some missionary biographies, but I cannot recall which ones). You can see that I would sometimes get on a theme. I do not offer these as the best books, and I would not even offer all of them as suggestions (were I to do it over, for instance, I would not read Pollyanna to the girls). But they are all worth considering. Anyway, here they are. Continue reading Books I read my children
Love is patient, love is kind. It does not envy, it does not boast, it is not proud. It does not dishonor others, it is not self-seeking, it is not easily angered, it keeps no record of wrongs. Love does not delight in evil but rejoices with the truth. It always protects, always trusts, always hopes, always perseveres.
It is not hard to show that every single phrase in this Bible passage alludes to some portion of that section from Aristotle’s Rhetoric. Read more here: Rhetoric 2.4 & I Cor 13.
Either the Apostle Paul knew his Aristotle, or they have a nearly identical understanding of the love between friends.
- Be too cool to ask questions or learn anything new.
- Try not to think hard, but if you must think, compartmentalize your thoughts.
- Spend your free time indoors staring at a screen.
- Fear ideas that differ from your own, and never read anything you disagree with.
- Only be friends with people your own age who think like you.
- Avoid people who know more than you.
- Have no heroes.
- Never travel far from home, but if you must, stay only in comfortable places.
- Never think through what the Bible says about anything.
- Never pray.
HT: Brian Daigle.
Symbolic logic has five standard logical operators, each of which has a standard translation in English:
negation is “not”
conjunction is “and”
disjunction is “or”
conditional is “if/then”
biconditional is “if and only if”
While the translations of the first four logical operators are frequent in English, the phrase “if and only if” is used very infrequently, and then only occasionally among mathematicians, philosophers, and lawyers.
For instance, while it is easy to find hundreds of nots, ands, ors, and if/thens in the Bible, the phrase “if and only if” is completely absent. However, for those who look carefully, biconditional reasoning is used several times in scripture. Keeping in mind that p if and only if q means if p then q and if q then p — and remembering other equivalences we have learned — the following verses all reflect biconditional reasoning: Continue reading The Biblical Biconditional
One of the difficulties new students of symbolic logic must overcome is understanding the defining truth table for the conditional, the “if/then” logical operator. The defining truth table tells us what the truth value of the proposition is, given the truth value of its component parts. For the conditional, it looks like this:
p q p ⊃ q
T T T
T F F
F T T
F F T
One way to defend this is to look at real-life conditional propositions with known truth values, for which we also know the truth value of the component parts. We will take our examples from the Bible. Continue reading If/Then Truth Table
On the Square of Opposition, the particular affirmative is “Some S is P” and the particular negative is “Some S is not P.” Why does the universal “All S is P” not have the contrary universal “All S is not P”? Why instead do you use “No S is P”?
Just curious! Continue reading Logic and Biblical Ambiguities
A statement is a sentence that has a truth value, either true or false. Several types of sentences are not statements – questions and commands, for instance – because they do not have truth values. Another type of sentence that is not a statement can be called nonsense.
Nonsense sentences are not statements for the same reason as questions and commands; they cannot be said to be true or false. There are two types of nonsense sentences that we usually encounter in studies of logic. Continue reading Everything I say is a lie
I remember one technique you employed in logic class to teach enthymemes was the citation of examples of these in scripture. Have you ever used John 18:30? “They answered and said unto him, ‘If he were not a malefactor, we would not have delivered him up unto thee.’ ” Does that combine an enthymeme and a hypothetical syllogism? Continue reading Enthymeme in John 18:30?
While working on my upcoming rhetoric text I was reading Acts 26:24, where Paul’s defense is interrupted by Festus, saying, “You are out of your mind, Paul! Your great learning is driving you insane.” Festus’s assumption that great thinkers often go mad reminded me of Aristotle’s discussion of the degrading of human character in Rhetoric II.15, where he says, “A clever stock will degenerate towards the insane type of character.” Written about 400 years before the events of Acts 26, had Aristotle’s claim had become a familiar probability?