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Re:Category Theory, Syntactically (2016) by stillkicking on Thursday April 27, 2017 @06:13AM (#14210399)
I don't understand why anyone thinks step 1 in conveying any concept is definitions. This is not how brains work. Definitions are how you formalize your understanding once you've developed it. If this is meant to be an introduction, it's entirely backwards.

Also, if your examples are made only of the thing you're trying to explain, they're not examples.

Re:Category Theory, Syntactically (2016) by stillkicking on Thursday April 27, 2017 @06:28AM (#14210460)
Introduction to Cake Making

A cake is a baked good containing one or more edible substances, created by a baker. Cakes are made in a kitchen, using appliances, implements and utensils. An appliance is a powered mechanical device used to augment the baker's abilities, different from an implement and a utensil. Implements and utensils are unpowered tools used by hand to produce batter from ingredients. A batter is a mixture produced in stages, consisting of a base starch, proteins and flavoring agents.

For a concrete example of a cake, consider a cake containing one or more fruits. The fruit may be uniformly distributed among the cake's contents or clustered in toppings. This produces the cake's characteristic flavor and color, though color may also result from artificial coloring agents.

Through prolongued exposure to heat, we can transform batter into a cake. Molds may be used for this. Any bowls, spoons or whisks used in the process may contain residual batter suitable for direct consumption. [1]

In some ways I've stopped just when things were about to get good, but now you should have a solid understanding of the fundamentals.

[1] Licking is actually quite natural in this context.

Re:Category Theory, Syntactically (2016) by TeMPOraL on Thursday April 27, 2017 @12:24PM (#14212723)
This is Actually Good, and I'd love more stuff written that way!

No, seriously. Just look what this example does - it recursively provides a short description for each of the important concepts in the process of baking cakes. After reading this, I now feel I have a decent map of the topic - both what the things / processes involve and what they don't involve. I've also been introduced to domain terminology that will help me understand other sources.

--

As for original question, why definitions - I believe it's good to have precise definitions next to casual explanations of the same things, just so that the reader can quickly connect the casually discussed aspect with the precise definition, and answer some of their own questions (which authors can't predict) through thinking.

Re:Category Theory, Syntactically (2016) by stillkicking on Saturday April 29, 2017 @10:48PM (#14229940)
No it's terrible, and the fact that you don't notice is exactly the problem. See also: monads. If you understand the basic process of what's going on (preparing food) and what it's meant to do (produce a delicious treat), formalizing your understanding in this way feels like concise and clear insight. If you don't yet know anything, it will be meaningless word salad where each 'answer' produces a multitude more questions.

Note e.g. that I never once cited an actual cake, I merely provided an example of a category of cakes. This too is a problem with mathematics, so in love with their abstractions, they no longer notice the lack of the concrete.

Re:Category Theory, Syntactically (2016) by justifier on Thursday April 27, 2017 @06:56PM (#14215531)
Re:Category Theory, Syntactically (2016) by TuringTest on Thursday April 27, 2017 @06:42AM (#14210506)
This would actually be a very good introduction for a race of alien visitors who'd never heard of cakes, baking, or kitchens.
Re:Category Theory, Syntactically (2016) by shmageggy on Thursday April 27, 2017 @09:28AM (#14211278)
No it wouldn't for the same reason the article isn't a good introduction -- it relies on concepts that a naive reader doesn't understand. In your example the aliens are unfamiliar with kitchens, but the text mentions kitchens without ​any explanation. Similarly the article mentions and uses "sort" without any explanation. It seemed to be a fundamental concept but without any idea what a sort was I gave up. Every article on category theory does this.
Re:Category Theory, Syntactically (2016) by MichaelBurge on Thursday April 27, 2017 @01:16PM (#14213134)
There are 2 sentences between the first use of 'sort' and its explanation, which is that they are symbols with no interpretation. It looks like he defines function symbol before sort, presumably because function symbols are more important than sorts.
Re:Category Theory, Syntactically (2016) by jjaredsimpson on Thursday April 27, 2017 @11:41AM (#14212314)
This isn't true.

>Sorts and function symbols are just symbols. Something is a sort if it is in the collection of sorts. Nothing else is required.

If you gave up before reading this, then you didn't even read the 4th paragraph.

Re:Category Theory, Syntactically (2016) by bbcbasic on Thursday April 27, 2017 @06:51AM (#14210537)
If they are Vulcans or androids.
Re:Category Theory, Syntactically (2016) by Xophmeister on Thursday April 27, 2017 @07:04AM (#14210592)
More recipe books should be written by mathematicians ;)
Re:Category Theory, Syntactically (2016) by 1001101 on Thursday April 27, 2017 @09:31AM (#14211298)
Euginia Cheng, a category theorist, has written Cakes, Custard and Category Theory: Easy Recipes for Understanding Complex Maths, and How to Bake Pi: An Edible Exploration of the Mathematics of Mathematics.
Re:Category Theory, Syntactically (2016) by seanmcdirmid on Thursday April 27, 2017 @09:57AM (#14211458)
Re:Category Theory, Syntactically (2016) by andrzejsz on Thursday April 27, 2017 @02:57PM (#14213860)
This first title disappeared in favor of the second that is "How to bake Pi" I guess pure marketing move
Re:Category Theory, Syntactically (2016) by danidiaz on Thursday April 27, 2017 @05:03PM (#14214688)
Indeed, like "Burritos for the Hungry Mathematician" http://emorehouse.web.wesleyan.edu/silliness/burrito_monads....
Re:Category Theory, Syntactically (2016) by gumby on Thursday April 27, 2017 @11:48AM (#14212373)
After the proof that one may substitute slivered almonds for chopped crystalized fruit, I have a lemma that says one may substitute slivered almonds for a subset of the chopped crystalized fruit.
Re:Category Theory, Syntactically (2016) by vanderZwan on Thursday April 27, 2017 @11:14AM (#14212095)
So basically, the Guy Steele approach to cooking

https://www.youtube.com/watch?v=_ahvzDzKdB0

Re:Category Theory, Syntactically (2016) by wfisher on Sunday April 30, 2017 @10:03AM (#14231531)
Amazing. I couldn't agree more this is obviously a useless way to learn baking at first.
Re:Category Theory, Syntactically (2016) by diyseguy on Thursday April 27, 2017 @11:48AM (#14212370)
har! please do keep going
Re:Category Theory, Syntactically (2016) by mej10 on Thursday April 27, 2017 @09:55AM (#14211440)
Brains can work that way. It is a skill, and this skill even has a name: mathematical maturity.

Basically, after you've been exposed to a lot of mathematics you develop a skill where you can just accept abstract definitions and go with it.

Re:Category Theory, Syntactically (2016) by agentultra on Thursday April 27, 2017 @11:01AM (#14212003)
I would expect no less even in an introductory text. Mathematics is meant to be precise and formal mathematics even more so. Prosaic pedagogy might suit a liberal arts introduction but it won't help the reader to convince themselves that the statements and theorems proposed are true and valid.

The syntactic approach is really useful as a programmer. A Logical Approach to Discrete Math[0] teaches programmers how to develop proofs in this style using logic and syntactic substitution. Once shown how easy it is to achieve rigour it is hoped that work-a-day programmers can formulate their own proofs and develop stronger specifications using mathematical tools.

I'm not a formally trained mathematician and am completely self-taught as a programmer but with some background in set and graph theory I found it approachable. It's certainly a good companion text to learning more practical systems like TLA+ or Lean.

[0] https://www.amazon.ca/Logical-Approach-Discrete-Math/dp/0387...

Re:Category Theory, Syntactically (2016) by skybrian on Thursday April 27, 2017 @02:53PM (#14213825)
Great that it works for you, but it won't convince anyone of anything if they don't understand what it means or why they should care.

As a writer or a teacher, if you want to reach a broad audience, give some simple, concrete examples, then explain the abstraction that covers them all. Assuming mathematical maturity won't help you reach your audience.

Re:Category Theory, Syntactically (2016) by mijoharas on Thursday April 27, 2017 @10:51AM (#14211902)
This makes me think about formalised notation. If you have a mathematical formalised notation, you can express things either more expressively, or with less ambiguity (or both) than without it.

One thing that is required by a formal notation is that before you write a statement in your formalised notation, you need to define the terms and symbols and how they interact with one another or the statement makes no sense to the reader.

I would say this is true even when you're trying to use words rather than some type of syntax, because what you are trying to do is paint a very specific picture (or concept) in peoples minds, and you need these definitions there or people wouldn't understand them.

If you're trying to be concise and to constrain the space of possible interpretations of the words you have written, to only contain the concept that you are trying to explain, and not contain other valid interpretations of the words, that may disagree with the concept you are trying to get the reader to explain, the easiest way to do so is probably with up-front definitions of the terms you are about to use.

TL;DR I posit that an up-front definition of terms simplifies explanation of formal notation (or words) which is necessary to constrain the semantic idea-space to only the valid definition trying to be conveyed.

Re:Category Theory, Syntactically (2016) by lmm on Thursday April 27, 2017 @06:31AM (#14210470)
This is explicitly a syntactic approach. It's treating this as a game you play with symbols. I found it very helpful, so maybe some brains work differently from others.
Re:Category Theory, Syntactically (2016) by dualogy on Thursday April 27, 2017 @06:49AM (#14210524)
> Definitions are how you formalize your understanding once you've developed it

You probably already "developed it" if you're looking back on even just a few years of full-time coding, typically "multi-paradigm" anyway (imperative, "functional" when you dig out SQL, denotative/descriptive for the common web DSLs html/css).

You never formalized or looked for existing formalizations of your organically acquired & accumulated intuitions and "instincts" (covering numerous little assimilated-by-osmosis laws and relations and "ittt" implications) because no real need ever arose, nothing in the real world prompted you to, and if the passing thought to do so ever occurred to you briefly, you saw no particular promise in going down that rabbit hole. I think that's the bulk of C.T. (just covering logical/mathy sciences/fields from a higher-vantage-point in a blurrier meta way). Once you would do so, you'd find it also shockingly hard to really interrelate and out-formulate and staking-off-boundaries those, figuring out "the laws of the laws" etc.

Admittedly, this my current assessment of "category theory" may be quite incomplete, pending further future insights & compelling persuasion to reassess it from scratch.

((( NB. imho we current crop of developers (and indeed most other "brainy" disciplines I'd wager) in many ways (besides of our syntaxes, schemas, algos, type systems that form the core "laws of nature") are still quite a bit like our stone/ice-age ancestors: in a way they enjoyed quite a grasp of the various facets (related to survival & thrival) of physics, biology, botanics, some chemistry, some "meteorology", geography and much more --- BUT strictly local, not formalized, formulated, no formal core/base language such as maths, and seeing no need for any of it to put fresh mammoth on the table. Quite an enjoyable state of affairs, too --- until you run out of mammoths and need to invent agriculture, thus cities, thus money, thus maths, thus science, not necessarily in that order =) so even though coding seems rigid and formal, a large part in reality is somewhat primal/instinctive/intuition-from-experience and stuff like C.T. is the "meta" attack on this organically-grown primitive (though again, tremendously enjoyable for the coder himself) state of affairs.. )))

Re:Category Theory, Syntactically (2016) by johncolanduoni on Thursday April 27, 2017 @07:26AM (#14210688)
> Also, if your examples are made only of the thing you're trying to explain, they're not examples.

Uh, no? Are you really arguing that (e.g.) a book teaching a programming language has no examples unless some of them are in another language? How on earth do you learn your first one?

Re:Category Theory, Syntactically (2016) by klibertp on Thursday April 27, 2017 @10:21AM (#14211630)
Strictly speaking all programming language books have the examples shown in two languages: the programming one and the natural language.
Re:Category Theory, Syntactically (2016) by gone35 on Thursday April 27, 2017 @12:04PM (#14212533)
If your examples are made only of the thing you're trying to explain, they're not examples.

That's just recursive definition. Some concepts demonstrably can't be exemplified otherwise.