Modal Logic: Axioms and Systems for Alethic Modal Logic

An image of multiple instances of the planet Earth.

Author: Thomas Metcalf Category: Logic and Reasoning, Metaphysics Word count: 992 Philosophical arguments are usually about what’s actually the case: whether it’s actually true that God exists or whether it’s actually true that we have free will. But commonly, we also want to talk about whether something is possible or impossible, or whether it might … Continue reading Modal Logic: Axioms and Systems for Alethic Modal Logic

Classical Syllogisms

The traditional "square of opposition."

Author: Timothy Eshing Category: Logic and Reasoning, Historical Philosophy Word Count: 999 Consider this argument: All humans are mammals. All mammals are animals. Therefore, all humans are animals. It’s an example of a classical syllogism. The logic of syllogisms, which are special kinds of deductive arguments, was famously discussed by the ancient Greek philosopher Aristotle … Continue reading Classical Syllogisms

Formal Logic: Symbolizing Arguments in Quantificational or Predicate Logic

Rudolf Carnap’s notes on Gottlob Frege’s Begriffsschrift, the progenitor of modern quantificational logic.

Author: Timothy Eshing Category: Logic and Reasoning Word count: 1000 Editor’s note: for many readers, this essay would be more profitably read after reading Formal Logic: Symbolizing Arguments in Sentential Logic by Thomas Metcalf. There are many varieties of formal logic of varying complexity. Here we survey one that’s somewhat more complex than sentential or … Continue reading Formal Logic: Symbolizing Arguments in Quantificational or Predicate Logic

Pascal’s Wager: A Pragmatic Argument for Belief in God

Pascal's wager image: person praying in front of a pile of poker chips.

Author: Liz Jackson Categories: Philosophy of Religion, Epistemology, Historical Philosophy, Logic and Reasoning Word Count: 996 Should you believe there’s a God? To answer this, we might examine arguments for theism—like first-cause and design arguments—and arguments for atheism—like arguments from evil. These arguments offer evidence for and against God’s existence.[1] Pascal’s wager, originally proposed by … Continue reading Pascal’s Wager: A Pragmatic Argument for Belief in God