Time Travel in the Dresden Files

[g33k]

What's the difference?

PentaGRAM is a 5pointed star.

PentaCLE is a pentagram inscribed in another figure, usually a circle.

PentaGON is a 5-sided shape, without any star/etc (like a hexagon is 6-sided (q.v. "hex paper, hex map")).

Pedantically yrs, etc.
- g33k
 

[Bad Alias]

pen·ta·cle
/ˈpen(t)ək(ə)l/
Learn to pronounce
noun
a talisman or magical object, typically disk-shaped and inscribed with a pentagram or other figure, and used as a symbol of the element of earth.
another term for pentagram.

This is the sort of thing I was talking about. I guess my point, if I even have one, is that unless Jim/Harry specifically described the shape or defined both terms (which I honestly can't recall if he did), there's enough usage variation that we can't be sure which it is.

I agree with g33k's definitions, but I'm generally uncertain of any speaker's definition (except for pentagon).

[morriswalters]

This overlapping magic penta whatevers are a staple of anime about magic. 

[toodeep]

You can't make a complex geometric structure out of a lot of circles with stars in them (it will have gaps).  The description of the structure of the island (I think) detailed the tips of stars meeting , and stars being placed inside stars, etc.  The inside of a star makes a pentagon.  If you directly connect the tips of stars, you make a pentagon.  So I assumed the basic structure of the prison is pentagons, thus the comment about the 12-sided die (dodecahedron).

[Bad Alias]

@toodeep: If I recall correctly, the description of the Prison is an idiots guide description of the Prison for Harry's sake. Kind of like how they still used Niels Bohr's model of an atom when I was in school even though "everyone" knew it was a pretty big oversimplification of what's going on.

Or maybe an even better example is how they told me and my classmates that "you can't subtract a bigger number from a smaller number" e.g., you couldn't do 4-10=-6. No this isn't a better example because that's not an oversimplification; it's just wrong, but since I typed it, I feel like sharing this horror with the world.

[Bad Alias]

I found where a pentangle had been inscribed on the stone, a five-pointed star within
a circle, like the one around my neck.

Changes, Chapter 41, Paragraph 1 (Page 344 of the hardback). So now we have another pentawhatever to deal with.

[didymos]

Changes, Chapter 41, Paragraph 1 (Page 344 of the hardback). So now we have another pentawhatever to deal with.

Pentangle is just another word for pentagram.

[morriswalters]

The symbology of pentacles or pentangles mean nothing in terms of how Demonreach is connected in time, they are just symbols like block printing.  They are two dimensional.

Jim does callouts. 
The law that forbids time travel says.

Thou Shalt Not Swim Against the Currents of Time

Out of nowhere in Dead Beat,

"It gets sort of Zen after a while," Butters said brightly. "Life is a journey. Time is a river. The door is a jar."

And finally in Changes just to be aggravating Jim tells you of a river that flows uphill.

I checked my mother’s memories and nodded as I reached the pitcher’s mound. “Okay, folks. First leg here. Should be a simple walk down a trail next to a river. Don’t get freaked when you notice the water is flowing uphill.” I stared at the air over the pitcher’s mound and began to draw in my will.

Now this appears to be a metaphor about the arrow of time.

Now remember how Ivy is spoken of in Small Favor.

“Drive one insane,” Luccio said. “Yes. And it generally does. There is a reason that the historical record for many soothsayers and oracles presents them as being madwomen. The Pythia, and many, many others, were simply the Archive, using her vast knowledge of the past to build models to predict the most probable future. She was a madwoman—but she was also the Archive.

Now in Turn Coat with Rashid,

Then he did something strange. He exhaled slowly, his living eye closing. The gleaming steel eye tracked back and forth, as if looking at something, though I could only tell it was moving because of the twitches of his other eyelid. A moment later, the Gatekeeper opened his eye and said, “The chances that you’ll survive it are minimal.”

And now the Mothers in Cold Days.

Calculation and thought flickered through those green eyes, faster than I could follow. "Ah, yes. I see," Mother Summer said. "So many new futures unwinding."

Both Rashid and the mother seem to be using calculations of the paths forward at specific events, Rashid looking at the possible outcomes in Turn Coat and the Mothers looking the possible futures after Harry learns one of the names of the Adversary.  This is what I have so far about predicting the future in the DF and traveling in time.

[Bad Alias]

Pentangle is just another word for pentagram.

No, it's another word for pentacle. 

[g33k]

...  This is what I have so far about predicting the future in the DF and traveling in time.

If you are actually collecting this stuff, you want to get the things Vadderung tells Harry too -- about "conservation of history" or some such.  I think it was Cold Days.

[toodeep]

If you are actually collecting this stuff, you want to get the things Vadderung tells Harry too -- about "conservation of history" or some such.  I think it was Cold Days.

Same with later in the book when "time is turned against them" and Vadderung must be used as a stepping stone to help move them through the river of time.

[morriswalters]

Vadderung's most useful points were in correcting Bob and in making the point that Harry had already saved the day.