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 […]

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 […]

“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 […]

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 […]

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 […]

“[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 […]

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 […]