Perpendicularity

A perpendicularity is a reliable interchange between the Physical Realm and the Cognitive Realm.

In general, perpendicularities are created by the presence of a Shard on a world. The concentration of so much Investiture in the Cognitive and Physical Realms creates points of ... friction, where a kind of tunneling exists. At these points, Physical matter, Cognitive thought and Spiritual essence become one - and a being can slide between Realms.

The existence of a perpendicularity (which often take the form of pools of concentrated power in the Physical Realm) on a world is a hallmark of a Shard's presence. According to Khriss, this is what makes First of the Sun so interesting ... because there isn't a Shard in the world's system.

Perpendicularities are used by Worldhoppers such as Khriss and Hoid to travel between worlds. They are formed through the concentration of Investiture in the Physical and Cognitive Realms. As a result, most are commonly found at Shardpools.

Properties

According to Ivory, there is only a stable junction between Shadesmar and the Physical Realm when somewhat of a person remains within the Physical Realm at the time:

“	"Only when a piece of you is there," Ivory said. "Today, that is not. You are here, Jasnah. I am ... sorry."	”
–Ivory to Jasnah

Characteristics

Perpendicularities can be created. One would need a lot of Investiture - like a ton of Investiture, according to Brandon. But, basically what Jasnah does is create a little mini perpendicularity, and slips herself into the Cognitive Realm.

It is possible to create a perpendicularity large enough that one could move large groups of people through it, and/or a spaceship.

Also according to Brandon, it is not traumatic to go through most perpendicularities.

Known Perpendicularities

Honor's Perpendicularity
Fan art by Lauren Newburg[1]

First of the Sun

First of the Sun is notable for being a minor Shardworld with a perpendicularity. It is, presumably, Patji's Eye. Brandon has mentioned that it's dangerous.

Roshar

Cultivation's perpendicularity has been confirmed by Azure to be the pool in the Horneater Peaks.

Ivory suggests to Jasnah that Honor's perpendicularity might well be their way out of Shadesmar. That said, according to Brandon, Honor's perpendicularity moves.

When Dalinar opens Honor's perpendicularity, the King's Drop is not infused with Stormlight, although a wide range of gemstones are. No one mentions whether the opening infused the Oathgate gemstones, or those gemstones in Navani's fabrial device.

Scadrial

The pool below the Pits of Hathsin on Scadrial was the perpendicularity there before it was destroyed by Kelsier. The other known perpendicularity there, the Well of Ascension, was extremely dangerous during the imprisonment of Ruin.

Sel

The Shardpool of Devotion is located on Sel.

According to Brandon, there is a second Shardpool on Sel. This is presumptively the pool of Dominion.

Threnody

There is no stable perpendicularity on Threnody. Only very unstable ones that cannot be predicted easily exist there, and they have a somewhat morbid origin. Also, on Threnody, a perpendicularity is more a circumstance than a location.

Notes

According to Brandon, creating an artificial perpendicularity on demand is theoretically possible.

Speculation

It has been speculated that the Origin of the highstorms to the east may be a perpendicularity.

Q&A with Brandon

Q. In the cosmere we've seen Investiture manifest in different ways all across the systems. So I was wondering, when it comes to the powers of Dalinar, is it possible for that power to open a perpendicularity anywhere, say on Scadrial or any different planet? In a different way, where you could potentially combine all the Realms, open the doors for the Realms.

A. Let me say this very carefully. I'm being recorded now ... . Any time where you gather the right amount of Investiture in the right way, you are going to have kind of a version of a cosmere singularity, right? Which is where you are pulling the different Realms together into a kind of - you are piercing between them with a large amount of Investiture. So what's happening with Dalinar is both the bug and the feature at the same time. But it is not necessarily the only way. And once things are kind of, once the Spiritual Realm is being involved, time and space don't mean anything anymore on the Spiritual Realm. That's your answer.

Q. Could the Investiture of two different Shards with separate Vessels create their own perpendicularity together?

A. Two different - so like, the Vessels of two different shards, okay ...

Q. Yeah, not Harmony.

A. Yeah, yeah, yeah. This is plausible. There could be a mixed perpendicularity.

Q. Radiants are bound to Roshar because of spren, but does it apply to Dalinar's ability to open the perpendicularity? If we assume that's not a Bondsmith's ability, but somehow a Shard's power, can Dalinar open Honor's perpendicularity on another planet?

I don't think Dalinar's ability will have any impact on him being more likely to leave. Opening the perpendicularity creates a path from the Physical Realm to the Cognitive and Spiritual Realm, but it doesn't change the person's location. Going through the perpendicularity doesn't get someone further away from Roshar.

A. This is correct.