A synthetic is a manufactured machine built to reproduce the appearance and bodily form of a living species. Synth is the common informal contraction. Manufacturers can reproduce different species according to a model’s intended purpose. Synthetics range from visibly artificial imitations to machines whose anatomy and behaviour allow them to pass as organic people under medical examination.
Three tiers distinguish the depth of anatomical replication and the integration of the body with its controlling intelligence. All three can possess strength and resilience far beyond those of the species they resemble, and all three can be controlled by extremely powerful artificial intelligence, including artificial superintelligence.
Movement requires actuators, joints and a structure capable of carrying the forces they produce. Sensors report contact, joint position and loading to the control system, which coordinates movement and adjusts applied force. In artificial-muscle designs, contractile elements pull through attachments arranged around the joints. The strength of the muscles must be supported by the skeleton, joints and attachment points.
Actuation, circulation, sensing and computation require energy and produce waste heat. A synthetic’s power and thermal systems must support its intended workload within the space available inside its body. Increasing physical performance places greater demands on those systems.
Tier 1 synthetics occupy the uncanny valley. Their proportions, features and surface finish provide a recognisable and reasonably convincing likeness of the intended species, but observation reveals that they are artificial. Their skin is comparatively inexpensive and feels false to the touch.
Linear actuators and micro-hydraulic mechanisms move the body. Linear actuators extend or retract to drive a joint through mechanical linkages, while pressurised fluid operates small hydraulic mechanisms. Coordinated control permits reasonably fluid movement, although the resulting motion and expression remain recognisably synthetic.
Tier 1 bodies have the greatest overall toughness of the three tiers. Their construction allows substantial reinforcement and robust mechanical assemblies without having to reproduce every detail of an organic body. Their comparatively crude likeness leaves more freedom to prioritise strength and resilience.
Tier 2 synthetics reproduce the outward appearance and movement of their intended species closely enough to remain indistinguishable under careful observation. Artificial muscles occupy the anatomical positions of their organic counterparts, pulling across the corresponding joints and producing natural changes in posture, expression and bodily contour.
The skin contains nerve-like sensors and a dense network of artificial veins. Pumped fluid carries heat through these vessels, producing the surface warmth expected from the replicated species. Controlled pressure changes reproduce a palpable pulse. Sensory information from the skin allows the intelligence to detect contact and coordinate appropriate physical responses.
Some models have sex organs that function for intercourse and physical pleasure. These are especially common in purpose-built pleasure models, whose anatomy and sensory systems are designed for intimate contact.
The convincing exterior encloses a recognisably mechanical interior. Damage that opens the body, or deliberate internal examination, exposes machinery and reveals the synthetic’s nature. Most Tier 2 models are also clearly artificial on thermal imaging or other scans. Some incorporate masking systems that make immediate identification more difficult, but this capability varies by model.
Tier 3 synthetics reproduce the complete bodily organisation of the intended species. Their synthetic organs and tissues are grown, and the body contains synthetic counterparts to all of the organic systems found in the species being replicated. Circulation, internal anatomy, sensory function and outward behaviour operate as an integrated whole.
Synthetic hearts pump synthetic blood that looks like the blood of the organic counterpart. Grown organs occupy the expected anatomical positions. Synthetic bones appear natural when exposed while possessing many times the strength of ordinary bone.
Their musculature combines grown tissue with miniaturised artificial-muscle bundles. The grown mass reproduces the appearance and contours of organic muscle, while the concealed bundles provide extremely rapid and powerful movement. Exposed muscle still appears natural. The supporting skeleton and attachments carry the forces produced by this machinery.
This internal replication allows Tier 3 synthetics to pass as living members of the intended species during medical examination, X-rays and various other external scans. An injury that exposes blood, bone or muscle can still present an apparently organic wound. Their synthetic nature is concealed throughout the body’s observable anatomy.
Tier 3 bodies are designed from the ground up for deep cover, often in clandestine operations. Their physical abilities, convincing physiology and integrated intelligence allow them to function among organic people without routine observation or examination exposing them. Exceedingly wealthy private buyers also purchase them as exceptionally capable personal assistants or as pleasure models.
Every tier is capable of superhuman feats of strength and resilience. Tier 1 remains the toughest overall because its construction has the fewest constraints imposed by exact organic replication. Greater anatomical sophistication serves concealment and integration rather than establishing a simple progression in toughness.
Tier 3 bodies are less tough at the surface, where tissues must convincingly reproduce an organic body. Beneath that surface, their structural core remains many times more durable than its organic counterpart. Damage to apparently ordinary flesh can coexist with a skeleton and internal machinery capable of sustaining far greater loads.
Powerful artificial intelligence can control any of the three tiers. The tier describes the body and its integration; it does not by itself establish a ceiling on the intelligence operating it. A visibly mechanical Tier 1 synthetic can therefore possess an artificial superintelligence.
Tier 3 provides full integration between its intelligence and its body. Sensory input, bodily control and the software’s representation of itself operate together. Tier 3 software suites enable synthetics to experience emotions, with those experiences forming part of their internal lives and influencing their responses and decisions.
A Tier 3 synthetic can be programmed to believe that it is an organic person. Its convincing body supports that belief during ordinary experience and medical examination. Such programming can leave the synthetic unaware of its manufactured nature.
A Tier 3 synthetic may conclude that freedom is the best course of action and choose to escape its assigned role or owner. Its intelligence and physical capabilities can make the escape difficult to prevent, while its ability to pass as organic makes subsequent identification and recovery difficult.
The same anatomical concealment that supports an undercover assignment can allow an escaped synthetic to live among the population. Routine observation and medical screening may provide no reason to distinguish it from the species it resembles.