After reading The Ra Contact, more than a few people will probably find the decision to use “Archetypal Mind” in Music of the Spheres vs Ra’s “Archetypical Mind” somewhat questionable – I know I would. So let’s get this thorn addressed right away.
To begin with, while the two words are mostly synonyms, “archetypal” is the more accepted variant of the two. However, more importantly – and the main reason it was chosen – is that “archetypal” refers to that original model or blueprint itself from which actual manifestations of the idea are then created, whereas “archetypical” is more applicable to a specific manifestation of that blueprint. As an example, it’s more correct to say, “These archetypal forces drive all of creation” and “His reaction was archetypical” than the other way around. Considering that the book discusses the archetypes proper, “archetypal” felt like a more correct choice.
References:
* https://www.difference.wiki/archetypical-vs-archetypal
* https://www.askdifference.com/archetypical-vs-archetypal/