Psionics
All psionics is substratics, but not all substratics is psionics.
Psionics is an applied form of applied substratic manipulation, a power that all sapient beings are technically capable of expressing. While the vast majority of humans do not possess the ability to activate their psionics, races like the Ir'vaki have evolved bodies and minds that are specifically designed to increase their substratic capabilities, allowing them much greater control over these abilities. One's psionic ability is directly proportional to the size and complexity of their substratic consciousness network, as well as their own personal skill in utilising it.
Psionic abilities usually manifest as a form of neural communication (telepathy) or manipulation between individuals without the need for speech, and can also be utilised to exert physical control over manifolds (telekinesis). The sphere of one's own psionic influence is limited by an individual's personal ability, and usually caps out at an average level. More advanced psionic abilities, such as the ability to rewrite the consciousness of other sapients and even reality as a whole are possessed by individuals such as Exon and The Selerian Horror; entities that possess this level of ability are considered by Raven as being anomalous.
All psionic abilities require an energy input proportional to the actions taken. This preserves the laws of thermodynamics, as is a constant with the Substrate, and means that one of the gateways to higher psionic abilities is not only one's own mental fortitude and training but also the construction of one's body to deliver sufficient energy to their mind. This is the case with the Ir'vaki, who have evolved to allow massive amounts of energy to be channeled into their bodies to harness exceptionally powerful psionic abilities.
Abilities
One's own psionic ability level is usually divided into one of three categories: latent, innate, and anomalous. Most humans fall into the latent category due to the potential existing inside their consciousness subnet, but lacking the mental training and body to use it. Examples of species with innate ability include the Ir'vaki, who evolved specially designed bodies to channel energy and receive training in society from a young age to effectively utilise their abilities.
Anomalous abilities include entities such as Exon and the Selerian Horror, who possess psionic capabilities far beyond even the highest levels of innate ability, such as teleporting between dimensions, rewriting reality on demand or erasing individuals from existence. One such initiator for anomalous abilities is the exposure to an extreme amount of entropic radiation, such as that from a bridge opened directly to the entropic plane. This forces the rapid evolution of one's consciousness network; this is what happened in the Girvan Offshore Science Facility (GOSF) in the containment block, where bombardment of a human test subject with entropic radiation from the Avernus Cavity Reactor (ACR) below created the Selerian Horror.
Telepathy
Telepathy is one of the easiest forms of psionics to control. It allows one to communicate with other sapient entities directly, without the use of a physical medium such as light or sound. Telepathy is easiest if both parties communicating possess psionic abilities; telepathy with a non-psionic sapient is possible, but requires heightened ability. Likewise, telepathy can also be performed with multiple parties (like a conference call), but this requires heightened skill on the part of all individuals. Telepathy can be an attack vector for infohazards, as exposing one's mind directly to another elevates this risk significantly.
On the higher end of the psionic ability spectrum, telepathy can be used to read or erase memories of another sapient, cause hallucinations or pain, or even control one's mind without cooperation on the part of the subject. These higher-level abilities usually cause a large amount of strain and exhaustion on the initiator, unless they are exceptionally powerful.
Telekinesis
Telekinesis has a higher barrier to entry than telepathy, and allows one, in essence, to control substratic manifolds, or essentially physical areas or objects in space. Telekinetic abilities can range from simply interacting with and picking up objects from a distance to actually rewriting the manifold itself as a form of control over reality. The latter is only possible in exceptionally powerful psionic individuals and usually results in a large amount of physical exertion.