## Valid arguments, contingent truths & forms

n Proposition Symbol Explanation 1 Peter is gay. P1 Premise 2 Peter is male. Q From 1 Valid? Perhaps. A truth table with show: P Q ¬Q P∧¬Q T T F F T F T T F T F F F F T F If the superconjunction of all the premises and the negation of…

## Complete arguments

A complete argument is as argument that is stated or presented such that: 1. One can see all the propositions in the argument. 2. All the propositions in the argument are numbered. 3. It is explained what kind of purpose all the propositions have. (Premise, inference or assumption.) 4. All inferences are stated, it is…

## Validity and necessary truths

Validity is defined in a couple of ways. I like to define it like this: An argument is valid iff the superconjunction1 of all the premises and the negation of the conclusion is impossible. It sounds a bit unusual at first but it is worded that way to prevent confusion about modalities. A more common…

## Truth tables and necessary truths

In the essay Validity and necessary truths I used truth tables with necessary truths and impossibilities in it. I did it like this: P □Q P→□Q T T T F T T Note that the modal operator is placed in the truth table also. It could also be done like this: P Q P→Q T…

## Quote of the day: Jake "Leaf" Greenleaf

Concerning a formal debate with a theist: “I’m not telling the theist how to affirm, I’m saying how to present it. A numbered list of premises, inferences and a conclusion would be required, because informal debating is terrible for pointing out fallacies.” Ain’t that the truth! Unfortunately not many people realize this and the world…

## Logical impossibilities

What does impossible mean? Other than ‘not-possible’. Logical impossibility is the topic of this essay. More specifically we’re going to explore the two distinct meanings of logical impossible that I briefly mentioned in a previous essay A journey into possibility land.1 The two logical impossibilities The two kinds of logical impossibility are absolute and relative…

## Some modal fallacy whine

Given how much debate the modal fallacy have spawned on FRDB, it’s interesting to note how little two academics wrote about it when they encountered it while discussing knowledge skepticism: 2. If a belief could be mistaken, then it is not knowledge. “The phrase ‘could be mistaken’ is susceptible to a number of interpretations. According…

## Definition of 'a probability'

A probability is something that is more than a mere logical possibility. I also think that it is stronger than a mere physical possibility (I’m a regularity theorist). Here’s one definition of it: p is a probability iff Pr(p)=>0. I’m not sure about this definition. It may be that my proposed definition is best taken…