Definition
Homeostasis
Homeostasis is the capacity of a biological system to keep relevant internal variables within a viable range despite external disturbance. It is achieved by sensing deviations, comparing them with a preferred state, and acting so that the deviation is reduced.
Mechanism
Homeostasis is usually implemented by feedback loops.
Core parts
- A variable that matters, such as temperature, pH, or glucose concentration.
- A sensor that detects the current value.
- A reference or tolerated range.
- An effector that changes the system when the variable drifts too far.
The key point is not stasis but controlled stability. A homeostatic system may fluctuate continuously while remaining within bounds.
Anatomical Homeostasis
In Michael Levin’s work, homeostasis is not limited to physiology. Cells and tissues can also maintain large-scale anatomical outcomes. On this view, morphogenesis and regeneration are forms of control in an anatomical state space: the system detects that the current form is wrong and acts to restore a preferred one.
This is why Levin often treats regeneration as a cognitive and cybernetic process. The tissue does not merely execute a fixed sequence. It can compensate for perturbation and still reach the same large-scale result. In that sense, anatomical homeostasis is closely related to scale-free cognition and depends heavily on bioelectricity.
Examples
Physiological homeostasis
Mammals regulate body temperature by sweating, shivering, changing blood flow, and altering behaviour. The exact state varies, but the organism keeps temperature within a narrow viable range.
Anatomical homeostasis
In regeneration, a tissue may rebuild a missing structure and stop when the overall pattern is restored. The important point is that regulation targets a form, not just a chemical concentration.