Interactive Tutorial of the Sequent Calculus This interactive tutorial will teach you how to use the sequent calculus, a simple set of rules with which you can use to show the truth of statements in first order logic. It is geared towards anyone…

http://blog.ram.rachum.com/post/54747783932/indescribable-numbers-the-theorem-that-made-me-fall-in

Ship of Theseus - Wikipedia, the free encyclopedia The ship of Theseus, also known as Theseus's paradox, is a paradox that raises the question of whether an object which has had all its components replaced remains fundamentally the same object. The pa…

The acts of the mind, wherein it exerts its power over simple ideas, are chiefly these three: 1. Combining several simple ideas into one compound one, and thus all complex ideas are made. 2. The second is bringing two ideas, whether simple or complex, together, and setting them by one another so as to take a view of them at once, without uniting them into one, by which it gets all its ideas of relations. 3. The third is separating them from all other ideas that accompany them in their real existence: this is called abstraction, and thus all its general ideas are made.*

Schneier on Security: A Link between Altruism and Fairness A blog covering security and security technology.…

Logic is the art of thinking; grammar, the art of inventing symbols and combining them to express thought; and rhetoric, the art of communicating thought from one mind to another, the adaptation of language to circumstance.

"...if you take any article, click on the first link in the article text not in parentheses or italics, and then repeat, you will eventually end up at 'Philosophy'."*

[...] there are three classes of men—lovers of wisdom, lovers of honor, lovers of gain*

From a 1977 Philosophy and Literature interview with Jorge Luis Borges:

No, what I mean to say is that I have no personal system of philosophy. I never attempt to do that. I am merely a man of letters. In the same way, for example that — well, of course, I shouldn’t perhaps choose this as an example — in the same way that Dante used theology for the purpose of poetry, or Milton used theology for the purposes of his poetry, why shouldn’t I use philosophy, especially idealistic philosophy — philosophy to which I was attracted — for the purposes of writing a tale, of writing a story? I suppose that is allowable, no?

Early Modern Texts - Philosophers and Philosophy Topics Here are versions of some classics of early modern philosophy, and a few from the 19th century, prepared with a view to making them easier to read while leaving intact the main arguments, doctrines, a…

 [The Internet Encyclopedia of Philosophy]

Stolen Ren Descartes Letter Is Being Returned to Its French Home - NYTimes.com It was the Great Train Robbery of French intellectual life: thousands of treasured documents that vanished from the Institut de France in the mid-1800s, stolen by an Italian mathematician. Among them …

The PhilPapers Surveys