Archive for September, 2009


Posted in Faith & Science on September 27, 2009 by daviddiel

“Agnosticism, in fact, is not a creed, but a method, the essence of which lies in the rigorous application of a single principle.”

“Positively the principle may be expressed: In matters of intellect, follow your reason as far as it will take you, without regard to any other consideration. And negatively: In matters of the intellect do not pretend that conclusions are certain which are not demonstrated or demonstrable. That I take to be the agnostic faith, which if a man keep whole and undefiled, he shall not be ashamed to look the universe in the face, whatever the future may have in store for him.”

-Thomas Henry Huxley

Review of District 9

Posted in Music-Movies-Media on September 21, 2009 by daviddiel

District 9 is about feeling like a dirty insect refugee at the mercy of a genocidal militant para-governmental agency. I’m sure there were parallels to South Africa under Apartheid.

As a sci-fi film, it was full of holes. For example, the aliens have a body suit that, by itself, can stop bullets in mid-air and throw them back at people. Impressive, right? But, when the main character, Wikus, gets into the suit, it takes lots of damage and fails.

Meanwhile, Wikus waffles between blowing multiple people away with spider missiles and feeling unable to kill individuals because of his great compassion. What kind of hero is sorta maybe on a mission? There’s also his wife, who totally loves him, then totally betrays him, then kinda loves him again. Huh?

Overall, its unfamiliar and creatively presented themes coupled with decent acting kept my interest. I mildly recommend watching it on DVD with a cold beer in hand to prevent over-thinking.

Proposal for a new two-axis grading system

Posted in Education on September 8, 2009 by daviddiel

I have often thought that the academic grading system should provide two characteristic numbers corresponding to two fundamental measures of information:

1) Comprehension (C) — What breadth of explanation, creativity, or ambition has the student expressed?

2) Percent Error (PE) — How much of the student’s expressed knowledge contradicts accepted knowledge?

This is how the proposed system would work. On a given test or assignment, a student who answers every question gets all the Comprehension points. Answer half the questions and get half the Comprehension points. Then, Percent Error is calculated based on number of questions answered and the number of mistakes.

A simple example would be a student who answers 4 out of 10 questions and 3 answers are correct (1 answer is incorrect). Using the two-axis grading system, the resulting scores would be C=40 and PE=25. This provides a point in a fundamentally meaningful two-dimensional space. For those who are familiar with information theory, this grading system measures the student’s Receiver Operating Characteristic (ROC).

This new system actually simplifies grading in many cases. Late work or missing answers get penalized in their C score, without affecting PE. Creative assignments become easier to grade, because the overall creativity or lack thereof goes into the C score without concern for technical flaws, which show up in PE. Classes with mixed levels of students can require students to show different levels of comprehension in order to achieve the same numerical score. Most importantly, it lets the student express directly how much he claims to know without encouraging Bogus Solutions (BS).

Teachers often ask “What if I have to give a single score? Won’t that score be the same as I would have given using the old system?” The answer is that you can reduce C and PE to a Single Score (SS), but the result will be different only if you grade on a curve. The formula is SS=(C/100)*(100-PE). If you curve, then the curve is only applied to C based on its mean value across all students. This method provides a better measure of information than curving SS based on the mean value of SS across all students.