Quotes About Logic

The heart knows no logic beyond need and desire; the head has no senses except the common and the pragmatic. Neither, frankly, is particularly useful in love, anyway.

All proof begins with something which cannot be proved, but can only be perceived or accepted, and is called an axiom or first principle.

Paradox is not just a logician's art. It is every man's tool to understand the real world we inhabit for a short time, and how it shapes our everlasting life. Paradox is a tool so common that a carpenter once used it to explain the depth of our existence.

improvement over the older Catholic idea? Chesterton says that modern thinkers will not follow new ideas to their logical end; nor will they trace traditional ideas back to their beginnings. If

Reason generates the list of possibilities. Emotion chooses from that list.

The only defence against raw, naked feeling was reason. Understanding made sadness easier to bear.

But when our faith causes us to check our brains at the door, we have fallen far from the God who gave us the capacity for reason.

only because language has something in common with the world that it can be used to picture the world, so it is only because of logic that our sentences have meaning at all.

The great advantage of the reductio method is that it allows us to tell if a statement is true, even if we do not know how to construct a proof for it. We can tell a statement is true by showing that its negation leads to a contradiction.

Russell's point is that if the set is a member of itself, then by definition it can't be a member of itself. But if it is not a member of itself, then it is a member of itself. So it is both a member of itself and not a member of itself. And that is a contradiction. This glaring mistake, allegedly, left Frege a broken man.

Gottlob Frege's Begriffsschrift.

If there are six apples on a table and you take away four of them, how many do you have?" Mr. Cooper asked. Andrea was waving her hand in the air like she needed to be rescued from a desert island. "Two apples!" she said. "Because six minus four is two." Then she made her smiley smile again. "No," said Mr. Cooper. "If there are six apples on a table and you take away four of them, you have four of them, of course. You just took four of them away!

leaders should be wary of common sense, which can be a poor substitute for evidence.)

Here are a few mind teasers to help you think in unexpected ways (see answers at end of chapter). • A bus with 15 passengers crashed and all but 9 people were killed. How many survivors were there? • How many animals of each species did Moses take on the ark? • I have 2 coins that total $.35 in value. One is not a quarter. What are the 2 coins?

An Investigation of the Laws of Thought, On Which Are Founded the Mathematical Theories of Logic and Probability.

If we were logical, the future would be bleak indeed. But we are more than logical. We are human beings, and we have faith, and we have hope, and we can work.

BOTH GÖDEL'S AND COHEN'S arguments proceed by constructing a model of set theory, though I will not explain them in detail.

Miyazaki's films bear witness to a keen understanding of animation as the most unfettered and potentially the most creative cinematic form thanks to its knack of transcending the laws of physics and biology, as well as flouting the expectations of logic and mimesis with carnivalesque gusto.

One of the most amazing things about mathematics is the people who do math aren't usually interested in application, because mathematics itself is truly a beautiful art form. It's structures and patterns, and that's what we love, and that's what we get off on.

This idea – that belonging needs to be continually refreshed and reinforced – is worth dwelling on for a moment. If your brains processed safety logically, we would not need this steady reminding. But our brains did not emerge from millions of years of natural selection because they process logically. They emerged because they are obsessively on the lookout for danger.

This idea—that belonging needs to be continually refreshed and reinforced—is worth dwelling on for a moment. If our brains processed safety logically, we would not need this steady reminding.

This idea—that belonging needs to be continually refreshed and reinforced—is worth dwelling on for a moment. If our brains processed safety logically, we would not need this steady reminding. But our brains did not emerge from millions of years of natural selection because they process safety logically. They emerged because they are obsessively on the lookout for danger.

Humans are not ideally set up to understand logic; they are ideally set up to understand stories." —ROGER C. SCHANK, cognitive scientist

The underlying logic of a living thing is its own survival.