Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

No, really, pi is wrong: The Tau Manifesto (Tau Day, 2010)

tauday.com

Post reply on HN
Print view View original

61–70 of 159 posts

Re: No, really, pi is wrong: The Tau Manifesto (Tau Day, 2010)

#61

Post by steveklabnik »

est wrote: post #52
steveklabnik wrote: post #5

Earlier quoted context omitted.

> infinite number The term you're looking for is 'irrational.' And tau is also irrational.

> The term you're looking for is 'irrational.' I think by infinite he means non-terminating. Conversely, an irrational number always has a non-terminating non-repeating decimal representation.

You're technically correct, the best kind.

I'd argue, however, that 'irrational' is closer to what he meant, than the exactness of what he said. Any time you move between a layman's understanding and a detailed technical one, the abstraction can leak.

I think 'irrational' matches up with intuition better, even if it's described as 'non-terminating.' People don't talk about 2/3 in the same way they talk about π.

Re: No, really, pi is wrong: The Tau Manifesto (Tau Day, 2010)

#62

Post by joe_the_user »

What I would like to see is an informational analysis where you take something like a thousand common equations and look at how they would be expressed with pi versus with tau. If you can show they would take significantly fewer bits of information using tau, then tau would be objectively superior.

Re: No, really, pi is wrong: The Tau Manifesto (Tau Day, 2010)

#63

Post by davidcuddeback »

steveklabnik wrote: post #51
tc wrote: post #2

Perfect; to my lisp startup file was just added: (defconstant tau #.(* 2 pi)) Regarding adoption, I think it's worth pointing out that these sorts of conventions can and do shift within a generation. I recall quite clearly while growing up the convention for indicating years = the year one [1] was B.C. and A.D. It seems like over the past few years we've definitively decided on B.C.E. and C.E. instead [2]. All it rea…

Ugh, I know this is slightly offtopic, but there's nothing more I dislike than B.C.E and C.E. I can understand not trying to promote a Christian-centric worldview, but by only changing the labels, they accomplish nothing. Now, the birth of Christ sets a 'common era,' which arguable makes it _more_ 'offensive' than just acknowledging what happened on that particular day.

The switch to B.C.E. and C.E. is also because the year of Jesus' birth is debated. Some believe he was born in 4 C.E. At least that's what I recall from school many many years ago. Personally, I prefer "B.C." and "A.D." because those two are more different from each other (edit distance of two) than "B.C.E." and "C.E." (edit distance of one, unless you count periods).

Edit: Wikipedia says Jesus was born in 5 B.C. (http://en.wikipedia.org/wiki/Jesus)

Re: No, really, pi is wrong: The Tau Manifesto (Tau Day, 2010)

#64

Post by sophacles »

lutorm wrote: post #46
jerf wrote: post #40

Earlier quoted context omitted.

You're operating under the wrong definition of "wrong". Axioms and definitions simply exist, but we are not therefore obligated to suspend all judgment on which ones are better for some purpose. I can reformulate all of physics to accept the Earth as a constant reference frame. It will be isomorphic to current physics based on being set in inertial reference frames, and therefore every bit as "correct" as conventiona…

No, no, no. Your Earth-centered physics is not wrong. It's perhaps "bad", or "awkward", "clumsy" or "suboptimal", but not wrong. The word wrong should be reserved for factually incorrect statements (unless you are discussing morals), otherwise it's been diluted to meaninglessness. It's better. See, you already agree with me. It's not "right", it may be "better" (though I question that fact, too.)

According to the OED, wrong as an adverb:

5. The fact or position of acting unjustly or indefensibly;

6. Not right or satisfactory in state or order; in unsatisfactory or bad condition; amiss.

7. a. Not adapted, according, or answering to intention, requirement, or purpose; not proper, fitting, or appropriate; unsuitable.

Any and all of which, but particularly #7, apply to the use of the term wrong in the tauday site.

Pi is [not adapted to purpose, not fitting].

See?

Re: No, really, pi is wrong: The Tau Manifesto (Tau Day, 2010)

#65

Post by aspiringsensei »

JeanPierre wrote: post #29

Part of me is saying yes, part of me is saying no. Let me elaborate: It makes all sense that tau should be the number used INSTEAD of pi: It simplifies things even more. (I hope I'm not the only one tired of writing 2*pi in papers.) But that doesn't make pi WRONG: It's defined by C/D, and the formulas make perfectly sense, even though you have to multiply by 2. Besides, it would mean a total rewrite of a lot of paper…

> total rewrite of a lot of papers, including a lot of mathematical books.

Somebody at the textbook publishers is smacking their lips at the prospect of selling an entirely new edition with an incredibly minor change.

Re: No, really, pi is wrong: The Tau Manifesto (Tau Day, 2010)

#66

Post by sophacles »

wwortiz wrote: post #10

Tau is an awful symbol in my opinion. If the people who support double pi as the true symbol they should be writing papers with a definition of double pi and truly proving to the mathematical community that pi is the wrong definition. I personally think pi*D is a perfectly sane way to describe pi and that thinking in 180 degrees is just as easy as in 360 degrees. Once the math community is convinced good luck with en…

So maybe instead of teaching in terms of the unit circle, we should switch to the unit semi-circle, as that would be 100% as easy to understand?

Re: No, really, pi is wrong: The Tau Manifesto (Tau Day, 2010)

#67

Post by jerf »

lutorm wrote: post #46
jerf wrote: post #40

Earlier quoted context omitted.

You're operating under the wrong definition of "wrong". Axioms and definitions simply exist, but we are not therefore obligated to suspend all judgment on which ones are better for some purpose. I can reformulate all of physics to accept the Earth as a constant reference frame. It will be isomorphic to current physics based on being set in inertial reference frames, and therefore every bit as "correct" as conventiona…

No, no, no. Your Earth-centered physics is not wrong. It's perhaps "bad", or "awkward", "clumsy" or "suboptimal", but not wrong. The word wrong should be reserved for factually incorrect statements (unless you are discussing morals), otherwise it's been diluted to meaninglessness. It's better. See, you already agree with me. It's not "right", it may be "better" (though I question that fact, too.)

If someone teaches or uses Earth-centric physics, I am perfectly comfortable calling that "wrong". They shouldn't do it. They are at the very least incurring opportunity cost and at worst actively harming the student.

Re: No, really, pi is wrong: The Tau Manifesto (Tau Day, 2010)

#68

Post by Naga »

steveklabnik wrote: post #51
tc wrote: post #2

Perfect; to my lisp startup file was just added: (defconstant tau #.(* 2 pi)) Regarding adoption, I think it's worth pointing out that these sorts of conventions can and do shift within a generation. I recall quite clearly while growing up the convention for indicating years = the year one [1] was B.C. and A.D. It seems like over the past few years we've definitively decided on B.C.E. and C.E. instead [2]. All it rea…

Ugh, I know this is slightly offtopic, but there's nothing more I dislike than B.C.E and C.E. I can understand not trying to promote a Christian-centric worldview, but by only changing the labels, they accomplish nothing. Now, the birth of Christ sets a 'common era,' which arguable makes it _more_ 'offensive' than just acknowledging what happened on that particular day.

There is another dating system which aims to get around this, by actually changing the numbers, which is called Before Present (BP). It sets 0 to be January 1, 1950, as an arbitrary date of the present. So, 1500 BP is 450 AD. I see it used most often it dealing with archaeology.

Re: No, really, pi is wrong: The Tau Manifesto (Tau Day, 2010)

#70

Post by seasoup »

Naga wrote: post #68
steveklabnik wrote: post #51

Earlier quoted context omitted.

Ugh, I know this is slightly offtopic, but there's nothing more I dislike than B.C.E and C.E. I can understand not trying to promote a Christian-centric worldview, but by only changing the labels, they accomplish nothing. Now, the birth of Christ sets a 'common era,' which arguable makes it _more_ 'offensive' than just acknowledging what happened on that particular day.

There is another dating system which aims to get around this, by actually changing the numbers, which is called Before Present (BP). It sets 0 to be January 1, 1950, as an arbitrary date of the present. So, 1500 BP is 450 AD. I see it used most often it dealing with archaeology.

Are you sure that April 20, 2010 isn't 0 BP? :)
Post reply on HN