I’ve found many people seem to confuse these terms, so here is a guide to their meanings.
Contherianthropy is a singular identity that encompasses both human and non-human aspects, remaining constant and unchanging in nature.
Unlike many therians who commonly feel they have both a human and non-human side, a contherian feels their human and non-human aspects are integrated to such an extent that they can not change. This means that unlike many therians, contherians do not experience any shifts. A shift being a change in state, from human to non-human or vice versa, relies on the fact that there is another aspect of yourself to shift into. For contherians this simply isn’t possible as there is no other aspect to themselves.
The absence of shifting does not mean contherians do not experience any influence from their non-human aspects, rather that these influences are set in nature and their strength does not change or shift over time.
Personally I have several constant feline phantoms. Some of these phantoms are stronger than others but each is set in it’s intensity and never wavers. I also feel as though I have a constant human-feline mindset.
There are times when I may act more human or more feline; during these times I am not shifting, rather choosing to follow one instinct over another. In other words, I’m always feeling the same degree of human and feline, but can pick and choose which course of action to take based on the situation. There may also be times when I don’t consciously choose, such as in an extreme situation where rationality goes out the window or while relaxed and performing an action subconsciously. However I act, the human-feline aspects of myself never change or shift in any way.
As contherianthropy describes an individual’s identity, contherians may experience some forms of shifting that are not limited by identity. For example, as dreams are a creation of the human mind and imagination, a contherian may shift into their theriotype during a dream – or into any other creature for that matter. Similarly astral shifts (shifts that take place in the astral plane) can be experienced as the mind can take on any form it wishes.
Cameo shifting can also affect contherians, as cameo shifts are not linked to a theriotype or personal identity.
Sometimes called syntherianthropy or suntherianthropy.
Similarly to contherians, vacillant therians also feel as though they have a non-human identity which is integrated into their human identity. The difference here is that vacillant therians experience this human-animal nature on a sliding scale. While there may not be distinct ‘sides’ to a vacillant therian, the degree of human-animal is not set.
Because of this vacillant therians do experience some degree of shifting, sometimes referred to as sliding shifts. Like contherians it is common for vacillant therians to always feel a partly non-human mindset and/or phantoms, however for vacillant therians these experiences can slide up and down the human-animal scale. Their phantoms may feel stronger or weaker at times and likewise their non-human mindset may also become stronger or weaker.
Some vacillant therians may shift more than others, some may only experience very minor fluctuations.
As with contherians, shifts which are not intrinsically linked to their identity are not affected.