quantum mechanics Quantum mechanics is the fundamental physical Scientific theory, theory that describes the behavior of matter and of light; its unusual characteristics typically occur at and below the scale of atoms. Reprinted, Addison-Wesley, 1989, It is ...

, internal measurement refers to the

measurement Measurement is the quantification of attributes of an object or event, which can be used to compare with other objects or events. In other words, measurement is a process of determining how large or small a physical quantity is as compared to ...

of a quantum system by an

observer An observer is one who engages in observation or in watching an experiment. Observer may also refer to: Fiction * ''Observer'' (novel), a 2023 science fiction novel by Robert Lanza and Nancy Kress * ''Observer'' (video game), a cyberpunk horr ...

(referred to as an internal observer or endo-observer). A quantum measurement represents the action of a

measuring device Instrumentation is a collective term for measuring instruments, used for indicating, measuring, and recording physical quantities. It is also a field of study about the art and science about making measurement instruments, involving the related ...

on a quantum system. When the measuring device is a part of the measured quantum system, the measurement proceeds internally in relation to the whole system. Internal measurement theory was first introduced by Koichiro Matsuno and developed by Yukio-Pegio Gunji. They expanded on the original ideas of Robert Rosen and

Howard Pattee Howard Hunt Pattee (born October 5, 1926) is an American biologist, Professor Emeritus at Binghamton University and Fellow of the American Association for the Advancement of Science. He graduated at Stanford University in 1948 and completed a Ph. ...

regarding quantum measurement in living systems viewed as natural internal observers that belong to the same scale of the observed objects. According to Matsuno, an internal measurement is accompanied by a redistribution of probabilities that leave them entangled in accordance with the

many-worlds interpretation The many-worlds interpretation (MWI) is an interpretation of quantum mechanics that asserts that the universal wavefunction is Philosophical realism, objectively real, and that there is no wave function collapse. This implies that all Possible ...

by Everett. However, this form of quantum entanglement does not survive in an external measurement, in which the mapping to real numbers takes place and the result is revealed in classical spacetime, as the

Copenhagen interpretation The Copenhagen interpretation is a collection of views about the meaning of quantum mechanics, stemming from the work of Niels Bohr, Werner Heisenberg, Max Born, and others. While "Copenhagen" refers to the Danish city, the use as an "interpretat ...

suggests. This means that the internal measurement concept unifies the current alternative

interpretations of quantum mechanics An interpretation of quantum mechanics is an attempt to explain how the mathematical theory of quantum mechanics might correspond to experienced reality. Quantum mechanics has held up to rigorous and extremely precise tests in an extraordinarily b ...

Internal measurement and theoretical biology

The concept of internal measurement is important for

theoretical biology Mathematical and theoretical biology, or biomathematics, is a branch of biology which employs theoretical analysis, mathematical models and abstractions of living organisms to investigate the principles that govern the structure, development ...

, as

living organisms An organism is any living thing that functions as an individual. Such a definition raises more problems than it solves, not least because the concept of an individual is also difficult. Many criteria, few of them widely accepted, have been pro ...

can be regarded as endo-observers having their internal

self-referential encoding Self-referential encoding is a method of organizing information in one's memory in which one interprets incoming information in relation to oneself, using one's self-concept as a background.Rogers, T. B., Kuiper, N. A., & Kirker, W. S. (1977). Self ...

. An internal measurement leads to an

iterative Iteration is the repetition of a process in order to generate a (possibly unbounded) sequence of outcomes. Each repetition of the process is a single iteration, and the outcome of each iteration is then the starting point of the next iteration. ...

recursive Recursion occurs when the definition of a concept or process depends on a simpler or previous version of itself. Recursion is used in a variety of disciplines ranging from linguistics to logic. The most common application of recursion is in m ...

process which appears as the

development Development or developing may refer to: Arts *Development (music), the process by which thematic material is reshaped * Photographic development *Filmmaking, development phase, including finance and budgeting * Development hell, when a proje ...

and

evolution Evolution is the change in the heritable Phenotypic trait, characteristics of biological populations over successive generations. It occurs when evolutionary processes such as natural selection and genetic drift act on genetic variation, re ...

of the system where any solution is destined to be relative. The evolutionary increase of complexity becomes possible when the

genotype The genotype of an organism is its complete set of genetic material. Genotype can also be used to refer to the alleles or variants an individual carries in a particular gene or genetic location. The number of alleles an individual can have in a ...

emerges as a system distinct from the

phenotype In genetics, the phenotype () is the set of observable characteristics or traits of an organism. The term covers the organism's morphology (physical form and structure), its developmental processes, its biochemical and physiological propert ...

and embedded into it, which separates energy-degenerate rate-independent genetic symbols from the rate-dependent dynamics of construction that they control. Evolution in this concept, which is related to

autopoiesis The term autopoiesis (), one of several current theories of life, refers to a system capable of producing and maintaining itself by creating its own parts. The term was introduced in the 1972 publication '' Autopoiesis and Cognition: The Realizat ...

, becomes its own cause, a universal property of our world.

Internal measurement and the problem of self

The

self In philosophy, the self is an individual's own being, knowledge, and values, and the relationship between these attributes. The first-person perspective distinguishes selfhood from personal identity. Whereas "identity" is (literally) same ...

can be attributed to the internal quantum state with entangled probabilities. This entanglement can be held for prolonged times in the systems with low dissipation without demolition. According to Matsuno, organisms exploit thermodynamic gradients by acting as

heat engines A heat engine is a system that transfers thermal energy to do mechanical or electrical work. While originally conceived in the context of mechanical energy, the concept of the heat engine has been applied to various other kinds of energy, part ...

to drastically reduce the effective temperature within macromolecular complexes which can potentially provide the maintenance of long-living

coherent states In physics, specifically in quantum mechanics, a coherent state is the specific quantum state of the quantum harmonic oscillator, often described as a state that has dynamics most closely resembling the oscillatory behavior of a classical harmo ...

in the

microtubules Microtubules are polymers of tubulin that form part of the cytoskeleton and provide structure and shape to eukaryotic cells. Microtubules can be as long as 50 micrometres, as wide as 23 to 27 nm and have an inner diameter between 11 an ...

nervous system In biology, the nervous system is the complex system, highly complex part of an animal that coordinates its behavior, actions and sense, sensory information by transmitting action potential, signals to and from different parts of its body. Th ...

. The concept of internal measurement develops the ideas of Schrödinger who suggested in '' "What is life?"'' that the nature of the self is quantum mechanical, i.e. the self is attributed to an internal state beyond quantum reduction, which generates emergent events by applying quantum reduction externally and observing it.

References

{{Reflist Philosophical theories Measurement

Internal measurement and theoretical biology

Internal measurement and the problem of self

See also

References