## Another case of someone who intuited the modal fallacy early on?

plato.stanford.edu/entries/moore/#2 So, on the face of it, this thesis has here been inferred from Leibniz’ Law. Moore observes, however, that the step from (1) to (2) is invalid; it confuses the necessity of a connection with the necessity of the consequent. In ordinary language this distinction is not clearly marked, although it is easy to […]

## A modal fallacy in linguistics

I’m writing this piece as i have gotten rather tired of explaining this point over and over. Writing an article about it saves me time. The form of reasoning goes something like this: 1. This person uses some other spelling than the standard one for a word. Therefore, 2. This person does not know how […]

## Dennett (1995) and th modal falacy

“In the “weak form,” it is a sound, harmless, and on occasion useful application of elementary logic: if x is a necessary condition for the existence of y, and y exists, then x exists. If consciousness depends on complex physical structures, and complex structures depend on large molecules composed of elements heavier than hydrogen and […]

## John Nolt – Logics, chp. 11-12

I am taking an advanced logic class this semester. Som of the reading material has been posted in our internal system. I’ll post it here so that others may get good use of it as well. The text in question is John Nolt’s Logics chp. 11-12. I remade the pdfs so that they ar smaller […]

## Propositions, cross-world identity and truth values

1. There is a thing, x, such that it is a contingent proposition. ∃xCx 2. For any thing, x, if x is a contingent proposition then there is a possible world, w, where x is true, and there exists a possible world, w’, where x is false. ∃xCx→∃x∃w∃w’Pxaw∧Pxbw’ 3. Thus, there is a thing, x, […]

## Bachelors and essential properties

When explaining the distinction between essential and accidental properties bachelors are often used. The idea of essential properties is this: The distinction between essential versus accidental properties has been characterized in various ways, but it is currently most commonly understood in modal terms along these lines: an essential property of an object is a property […]

## A note about modal collapse

Removed due to lack of quality.

## Infallible knowledge, the modal fallacy and modal collapse

The much mentioned the modal fallacy is not a fallacy (that is, is a valid inference rule) if one accepts an exotic view about modalities and necessities that is logically implied by a particular understanding of infallible knowledge and a knower. Infallible knowledge Some people seem to think that some known things are false and […]

## Language, the modal fallacy and the symbolic representation of a conditional

“[W]hat follows from a true premiss must be true” (The Problems of Philosophy, p. 60, link) Wrote Russell as an example of a principle of logic that is more self-evident than the inductive principle. If we were to formalize this we would perhaps write it like this: E1. □[([∀P][Q∧Q⇒P])→P]1 Or perhaps just just in propositional […]

## An appeal to skepticism about reasoning

Unaided and aided reasoning Humans reason about many things. Some things are more complex than other things. The more complex a thing is, the more probably it is that one will reason wrongly about it. For simple things the probability of unaided reasoning reasoning wrongly is not high. For complex things the probability of unaided […]