When I ran a Delta Green game the other week, one of the players (yes, the player, not their character) was hung up with having “magic” in the game. He could deal with millennia-old squid-headed aliens hanging out on the bottom of the Pacific, but not magic. I explained that magic was really just advanced science based on “hypergeometric principles” which satisfied him for the session, but I decided to work out a brief “scientific” description of how (much of) magic works within my game. It involves physics, vibrations and hand-waving. Mostly the latter.
The universe is multi-dimensional. We are limited in that we are trapped within three-dimensional bodies (that travel at an uncontrollable fixed rate along a fourth time dimension). However, that does not mean that other dimensions do not exist. We simply are not equipped (normally) to see or interact with these other dimensions. Physicists working in string theory have said there are as many as 11 dimensions but even that number may be lower than reality.
However, just because we are limited to three dimensions does not mean that everything is. Some entities exist that live in four, five or even more dimensions simultaneously. Some of these exist in dimensions that overlap with one or more of the ones we inhabit. Others may be around us all the time; invisible and undetectable because they do not overlap with us in any way but around us just the same.
Our minds (as opposed to our physical brains) are not limited to a subset of available dimensions. This is why these other entities are capable of contacting us in our sleep, in our dreams. The most famous example of this is Cthulhu himself, who lies “asleep but dreaming in his home in R’lyeh”. Just because his body is trapped does not mean that his mind is.
There are also ways to physically interact with these entities and the dimensions they inhabit. The two most common are resonance and congruence.
We will start with resonance. While not technically correct it is possible to think of these other dimensions as “vibrating” at a different frequency than we do. If certain frequency patterns are established, a “resonance” can be set up between our dimensions (or at least our fully-dimensioned minds within our dimensions) and the entities inhabiting other sets of dimensions. This is the principle behind many so-called “magical incantations”. The nonsense syllables and atonal music of magical rituals are not really meaningful in and of themselves. “Ph’nglui mglw’nafh Cthulhu R’lyeh wgah’nagl fhtagn!” is thus not necessarily a phrase in an unknown language so much as it is simply a phonetic way of re-creating a set of sonic vibrations that resonate with a particular entity in another set of dimensions.
And these dimensions may be at an arbitrary distance. Even if a place is a long distance away in the three dimensions we normally experience it may be quite close in another set of dimensions. It is said, for example, that Yog-Sothoth is co-terminus with all of time and space. It is. It does not normally exist within the four dimensions that we inhabit but in the set of dimensions it does normally dwell within it overlaps all of ours (though it is not abnormally large within its own planes of existence).
Science, of course, has made great strides in automating such “rituals”. The most well-known example of this is the Tillinghast Resonator (described in Lovecraft’s story From Beyond). This device creates electromagnetic frequencies that allow our minds to easily discern other dimensions. And for entities of those dimensions to discern us.
The other, related method of connecting with these other dimensions is simple geometry. If a particular geometric angle or structure is created that matches an angle or structure in another set of dimensions then a connection can be established between the two. A person or entity can then “translate” (for lack of a better word) from one set of dimensions to another. These are the “angles” and “non-Euclidean geometries” that Lovecraft spoke of. Angles and geometry feature heavily in Dreams in the Witch House, for example, where they seem to feature heavily in the witch’s powers. And the Hounds of Tindalos of course materialize from angles.
By looking at things from a multi-dimensional viewpoint, much of the so-called “magic” is explained. Summons work by translating entities from one set of dimensions to another. Gates work by shifting a traveller to another set of dimensions where their origin and destination are arbitrarily close to one another. The Mi-Go are mining substances we can’t see because they only exist in other dimensions (and they can survive in vacuum because “air” exists in the other dimensions there) and the Insects of Shaggi can pass into our skulls because they are open from other dimensions.
Multiple dimensions also explain such creatures as the Hounds and the Great Race of Yith. They also live in multiple dimensions but instead of being forced along the time dimension as we (and most other species) do, they can travel along it as easily as we can in the other three.
This gives a somewhat consistent and pseudo-scientific explanation for the “magic” encountered in Call of Cthulhu.
Of course, you can always just say it’s just magic. That works too.