Notice in the bulletin shown in Mike Rinder's post that Hubbard is conflating Squirrels with SPs.
A squirrel is supposed to just be someone who because they are not applying the tech standardly is going to fail and will never achieve clear or OT. Like all the people through history before them who didn't have Scientology they will go round and round like a squirrel on a hamster wheel getting nowhere and ending up where they started. Surely he didn't mean to imply that all the philosophers who came before him were SPs. He probably should have used “Hamster” because I think most people associate those wheels with hamsters but hamsters just don’t evoke the same impression of crazy like squirrels. That word picture is the origin of the term. But it is in the long list of descriptions of an SP that an SP instinctively tries to destroy anything good so here misguided squirrels and one of the fundamental characteristics of an SP are now the same. So from a Scientology standpoint you are also an SP simply by virtue of not applying Scientology standardly according to the organization's mandates or more importantly - in cooperation with the COS money scheme.
Over time the body of material defining an SP and how this is integrated into their extensive Machiavellian internal judicial procedure has made it so that it is extremely easy to designate someone as an SP. And because the source or incident responsible for making a person an SP can be traced back to a lifetime in a kicked-in-the-head alien society millions of years ago in a galaxy far far away, this all quickly becomes very subjective (read: UFO cult). LRH benevolently goes out of the way to make the point that we are supposed to apply all of this SP identification tech together as an integral body of knowledge and not condemn someone for displaying one or a few characteristics because often by being PTS or associated with the many SPs around us we sometimes just dramatize their suppressive valences, but in Scientology practice people are often labeled very arbitrarily and the higher the labeler is on the org board and the more the potential labelee still has assets that can be exploited the more fickle the labeling becomes.
If Hubbard was born 1400 years earlier he would have just said “Infidel” but Scientology is designed for modern clever people who are attracted to complexity and so Scientology has an extensive lexicon of euphemisms that essentially mean infidel or in the case of hero's lice - "vermin" worthy of extermination without sorrow.
http://suppressiveperson.org/1965/08/07/hcopl-suppressive-persons-main-characteristics-of/
(snip)
The whole rationale of the SP is built on the belief that if anyone got better, the SP would be for it as the others could overcome him then.
He is fighting a battle he once fought and never stopped fighting. He is in an incident. Present time people are mistaken by him for past, long-gone enemies.
Therefore, he never really knows what he is fighting in present time, so just fights.
12. The SP is sure everyone is against him personally and if others became more powerful they would dispose of him.
(snip)