Sequent Systems

Philosophy, formal logic, thoughts, curiosities - these are notes on interesting things, not necessarily things I agree with (or even understand). Some references are listed in the bibliography; bibliographic entries link back to posts. The bibliography is frozen - I now just record book titles with the page numbers next to them. The previous theme was "Linear" by petervidani; the current theme is "Asterism" by simenge. Audio posts no longer work, but I'm using this for the search function. (It's not particularly efficient, since I never tag anything - I should probably start. Searchable tags so far: #logic, #epigraphs.)

[sequentsystems-blog]

I now blog at http://studyinglogic.tumblr.com/ and don’t use this blog anymore - if you like my stuff, follow me there!

[mathprofessorquotes]

Using calculus to solve this problem would be overkill, like using a bazooka to kill an ant.

Calculus professor (via mathprofessorquotes)

[ceronprime]

[vjeranski]

HIROKO Nakajima Zusammenfluss b Acryl auf Papier 2012 78,8 x 53,8 cm

[mediumaevum]

Medieval Theories of the Syllogism

Medieval logic is divided into the old logic (logica vetus), the tradition stretching from Boethius (c. 480–525) until Abelard (1079–1142), and the new logic (logica nova), from the late twelfth century until the Renaissance. The division reflects the availability of ancient logical texts.

Before Abelard, medieval logicians were only familiar with Aristotle’s Categories and On Interpretation and Porphyry’s Isagoge or Introduction to the Categories and not the Prior Analytics, where Aristotle develops the theory of the syllogism — though they did know something of his theory through secondary sources. Once the Prior Analytics reappeared in the West in the middle of the twelfth century, commentaries on it began appearing in the late twelfth and early thirteenth centuries.

image: Historiated initial (!) on folio 4r from Boethius “On the Consolation of Philosophy”, probably Italy, c. 1385

[scientificphilosopher]

No tree, it is said, can grow to heaven unless its roots reach down to hell.

Carl Jung, Aion: Researches into the Phenomenology of the Self (via scientificphilosopher)

[philosophy-quotes]

The key to wisdom is this — constant and frequent questioning, for by doubting we are led to question and by questioning we arrive at the truth.

Peter Abelard (via philosophy-quotes)

[untiltheseashallfreethem]

(Apropos of nothing in particular.)

I’m annoyed at the idea that math is “just symbol-pushing”. That math has a bunch of clear, logical rules, and so all you need to do when solving a math problem is apply those rules [1].

This is not what makes math difficult. The hard part is not applying the...

[untiltheseashallfreethem]

Beneath the cut is an out-of-context, spoilery quote from Perelandra.  It probably doesn’t make sense unless you’ve read the book.  I’m posting it here for my own archiving purposes.

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[jadagul]

[snip]

People should do good things, but people shouldn’t set out to be heroes.  There’s a reason “I’m no hero, I just do what needs to be done” is a huge trope.

[sometheoryofsampling]

Happy are those who are beloved, and those who love, and those who are without love. Happy are the happy.

Jorge Luis Boges, ““Fragments of an Apocryphal Gospel” (via sometheoryofsampling)

[atumbledownhouse-deactivated201]

Perhaps some of our lives are best imagined not as novels but as books of short stories. If so, one might strive not to progress towards one goal but to behave in such a manner that its overarching themes can be of hope and virtue rather than despair and dereliction.

[a-beautifulchaos]

a-beautifulchaos: Luis Tomasello, ‘Atmosphere Chromoplastique N. 942,’ 2010

[thesociologicalcinema]

How to Steal an Election Nice illustration of the practice of gerrymandering, or manipulating district boundaries to remain in power. Source: Does anyone know who created the graph?

[vjeranski]

William Pittman Andrew Constellation Drawing

[patternsofbehavior]

One of the most common criticisms of conspiracy theories is that they are non-falsifiable, since any contradictory evidence can be written off as a fabrication, a false trail, or so forth. A conspiracy, moreover, must be well-hidden — lack of evidence is itself evidence! What is less frequently acknowledged is that the alternatives to conspiracy theories are very nearly non-falsifiable as well. Anyone who comes forth to expose a conspiracy can be labeled a fraud or a madman, and nearly anything can be written off as coincidence. We are faced, as we are so often in life, with two narratives that can, with perhaps a bit of stretching, account for all of the facts. How then to choose? Much as we would like to think otherwise, evidence and logic cannot bring certainty. Nor, as numerous social psychology experiments demonstrate, are they the primary determinants of our judgments and choices. Despite the epithets hurled back and forth, neither side of, say, the 9/11 conspiracy issue is stupid. Critics of conspiracy theories paint their proponents as naïve, unsophisticated, and guilty of obvious selection biases and a host of elementary errors in research and logic. I have found such critiques unsatisfactory. They certainly apply to the worst of the genre, but not always to the best. Reasonable people can, depending on their vantage point and life situation, look at the same set of events and form different beliefs about them. These beliefs then become a filter that determines what they see and, indeed, what they look for. It is as if they enter separate but parallel realities.

Charles Eisenstein:

Synchronicity, Myth, and the New World Order

(via patternsofbehavior)

[curiosamathematica]

Mathematical reasoning may be regarded rather schematically as the exercise of a combination of two facilities, which we may call intuition and ingenuity.

Alan Turing (via curiosamathematica)