“Philosophy, throughout its history, has consisted of two parts inharmoniously blended; on the one hand a theory as to the nature of the world, on the other an ethical or political doctrine as to the best way of living. The failure to separate these two with sufficient clarity has been a source of much confused […]

Fast: “We need to keep in mind that “I know that I know” is ambiguous between 1) I am certain and 2) I have knowledge that I know. The latter is very often true, but the former is very rarely true.” Emil: “Why do you think it is ambiguous between them? It seems to me […]

It has been thought for many years (especially since Hume’s first Enquiry1) that induction lacks a justification. This justification for induction, it has been thought for long, is necessarily if it is rational to use induction. The argument for why there is no justification, indeed there cannot be a justification, can be presented like this: […]

Induction and deduction are foundational to human rationality because it is impossible for a human to stop using them. Indeed what it means to be humanly rational is that one uses these reasoning systems. There is no sense in trying to discover any justification for these two reasoning systems because even if we discovered that […]

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 […]

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 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 […]

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 […]