D&D General how do the outer planes work?

[Bernese]

you mean its like the dreamlands from lovecraft?

As others have mentioned, there really hasn't been all that much serious thought put into the exact scientific and/or philosophical reasoning of the D&D Cosmology, and it definitely begins to break down fairly quickly when you look at it too deeply.
But although the original editions of D&D didn't quite officially explain it as such and more recent editions haven't delved any further into it, the basic idea is that concepts like Good, Evil, Light, Air, Thought, etc. are just as much the essential forces that make up the universe as gravity is.
And thus, as Monster Envy said, the general narrative idea is that outer planes are physical places that were, if not directly created, at least given form/substance by those concepts and ideas. Or, as Charlaquin said, perhaps we simply experience these purely conceptual planes as physical in order for us to make logical sense of them.

Or maybe it's aliens.

This is one of those questions that keeps coming up over and over ever since the game was invented, has changed and morphed as editions have come and gone, works differently for each table, and nobody's going to ever really get more than a superficial justification for it.

 

[UngainlyTitan]

you mean its like the dreamlands from lovecraft?

If you want.

 

[LordEntrails]

Pick a source, then run with it. There is no one way the planes have been presented. i.e. it varies by edition and source. Find the one that works for you and enjoy.

 

[bloodtide]

They work in mysterious ways.

For the Outer Planes, you need to forget what you (think) you know about reality. They are places of thoughts and concepts.....but "seem" physical. Maybe they only "seem" physical. Maybe it's just something that can't be understood.

You can dig into plenty of information about weird thoughts and dreams and places....just do a online search.

 

[Greenstone.Walker]

how do the outer planes work? if they are realms of pure thought and ideas, how come they work like physical places?

They are simultaneously physical places and metaphysical concepts.

Yes, it's something that mortal minds struggle to understand.

It's also possible that multiple cosmologies could be correct at the same time. Is the World Tree the correct model? Yes. What about the World Axis? Yes, that's true as well. How can they both be true at the same time? Quite easily. Just because your mortal mind can't comprehend something doesn't mean it can't exist.

 

[MechaTarrasque]

You can think of the outer planes as allegorical spaces. When you enter an outer plane, you are entering a story, and if the story "needs" you to interact with things, you do, and being solid, you probably need at least a few solid (or liquid) things to interact with to have a part in the story. In theory a LG character could climb faster up Mt. Celestia than a CG character that had the same stats, since matter, energy, space, and time are all controlled by the story. Since most of the lower planes are horror stories, they want you alive and awake, so that you can suffer more....

 

[EzekielRaiden]

how do the outer planes work? if they are realms of pure thought and ideas, how come they work like physical places?

That's the neat thing, they don't.

 

[jgsugden]

The DM has to decide.

In my setting, the planes are all physical locations. Souls and spirits are made manifest on some of them. Powers (Gods, Archfiends, Archfey, Elder Gods, etc...) have abilities to warp reality in some of the planes (or just in areas of some of the planes). The laws of nature function differently in some of them. However, they all feel roughly like physical places and are made of the same stuff as the prime material plane - although sometimes infused with different energies.

The only two planes that violate this rule are the Positive and Negative Energy Planes. However, only a small handfull of beings can survive for more than a moment on either of those planes. As such, they are huge mysteries.

 

[Blue Orange]

Trying to give it too much philosophical coherence is a fool's errand. They're places you can go to find and fight weird beings. Maybe they were sneezed out of the nose of a being known as the Great Green Arkleseizure and at 20th level your party has to stop the Coming of the Great White Handkerchief.

They're analogous to heaven and hell in orthodox Christian cosmology, I think. Thing is D&D went from lawful-vs-chaotic (effectively good-vs-evil) to a 2-axis system, so they had to have separate planes for those.

But once you had lawful and chaotic as well as good and evil you had to have lawful heaven and chaotic heaven (Olympus back then) and lawful hell and chaotic hell (the Abyss), and...then they had 9 alignments and put planes in between the various alignments, and then there were elemental planes named after the four classical elements, not to mention the para-elemental planes that mix two adjacent elements (water and air make ice? whatever) and quasi-elemental planes mixing a classical element with negative and positive energy...and you wind up with the mix of planes we have today.

 

[Mad_Jack]

They are simultaneously physical places and metaphysical concepts.

Yes, it's something that mortal minds struggle to understand.

On a slight tangent, in Steven Erikson's Malazan Book of the Fallen series, in addition to certain ideas and concepts having their own "planes", each individual mage is aspected to a particular type of magic (Fire, Light, Healing, etc.), and each type of magic is actually its own "plane" that casters of that particular type of magic can enter and travel through.