[umutcankus]

"How many holes exist in a straw?"

Any time I asked this question it produces some joyful brainstorming. It doesn't matter if it is a room full of highly technical people(engineers, mathematicians) or a family dinner.

I've already heard most of the arguments from the topological definition of a hole to difference between a hole, a cavity and a hallow but it is still very fun for me to watch people getting excited over such a boring looking question. (:

[gjm11]

You might enjoy https://andrewmbailey.com/dkl/Holes.pdfb on some related issues concerning holes, though IIRC it doesn't discuss anything equivalent to your question, which I think is as much mathematics as philosophy.

(I think I count holes, when in a rigorous sort of mood, by counting independent homotopy/homology classes of 1-dimensional loops in the complement of the object, so a straw has one hole, the surface of a ring doughnut has two, and e.g. a sock in good condition has none if you ignore the structure of the fabric it's made from. But meaning is contextual and I'm happy to talk about a "hole in the ground" which typically isn't a hole at all in this sense, and if someone said "did you know there's a big hole inside Mars", presumably meaning a cavity, I wouldn't object but would then be thinking of a different sort of topological hole.)

[umutcankus]

Thanks! But the url returns 404.

Also, probably I'm too engineer to understand the phrase "independent homotopy/homology classes of 1-dimensional loops in the complement of the object" so I don't know how this definition covers the case but an interesting extension to question is adding "holes" to the straw sideways. (exactly face to face or randomly located?, different sized if face to face?)

[AnonC]

There’s a typo in the link you shared (an extra “b” at the end) that leads to a page not found. The working link is https://andrewmbailey.com/dkl/Holes.pdf

[gjm11]

As a couple of people have pointed out, I somehow fat-fingered an extra character into that URL -- the "b" on the end should not be there. Too late to edit the comment now. Sorry about that!

[pbhjpbhj]

What's a hallow (as full a definition as you can provide without recourse to external references, please)? And, where are you from; what's your native tongue?

Thanks.

[umutcankus]

Honestly, I cannot give you a satisfying answer because I have no idea. I don't even know if there is a difference thinking in English.

I've transleted it from Turkish which is my native language. If the purpose of the question is to get some insight, I can give my intuition about it but that will be the opposite of "a full definition" (: When I see the word hallow ("oyuk" in Turkish) I think there is a opening in the structure otherwise has a solid body.

For example, a tree can have a hallow(hollow?)like this: https://www.elitetreecare.com/wp-content/uploads/2019/11/tre...

But it seems there is no strict boundary between the words, so if you say it is a hole I won't oppose that.

[nvilcins]

This is awesome! Does anyone have a collection of similar kinds of fun questions?

[becquerel]

Getting confused over holes has been a fun past time in academic philosophy for the past few decades, so trawling through the SEP for interesting topics can't hurt.