Functional information

The concept of functional information is an attempt to rigorously define the information content of biological systems. The concept was originated by a group led by Jack W. Szostak in 2003.^[1]

Definition

They define functional information as follows:^[2][3]

• the concept of degree of function is introduced, where the degree of function ${\displaystyle E_{x}}$ is a non-negative objective measure of the capability of system ${\displaystyle E}$ to do the physical function ${\displaystyle x}$ .
• the fraction of possible configurations of the system that can achieve at least a particular level of function ${\displaystyle \theta }$ in regard to the physical function ${\displaystyle x}$ is defined to be ${\displaystyle F(E_{x}\geq \theta )}$
• the functional information relative to a given level of function ${\displaystyle E_{x}=\theta }$ is defined as ${\displaystyle I(E_{x}\geq \theta )=-log_{2}F(E_{x}\geq \theta )}$

This leads to two conclusions:

• because all possible configurations can achieve zero or more functionality, that is to say ${\displaystyle F(E_{x}\geq 0)=1}$ , the minimum possible functional information for a system is ${\displaystyle -log_{2}1}$ , which is zero.
• for the highest possible level of a degree of function of a system ${\displaystyle E_{x}=\theta _{max}}$ , there will be a well defined ${\displaystyle I(E_{x}=\theta _{max})=-log_{2}F(E_{x}=\theta _{max})}$

Note that functional information of a system ${\displaystyle E}$ must always be defined relative to a specific function ${\displaystyle x}$ , without a choice of which it has no meaning.

Proposed law of increasing functional information

In 2023, a group of researchers proposed a law of increasing functional information, that asserts that a tendency to increase in functional information is an inherent property of the universe, encompassing both biological and non-biological systems.^[4][5][6]

The researchers postulated that evolving systems appear to be conceptually equivalent by displaying three notable attributes:^[4]

1. They form from numerous components that have the potential to adopt combinatorially vast numbers of different configurations;
2. Processes exist that generate numerous different configurations;
3. Configurations are preferentially selected based on function.

Subsequently, the authors proposed that the functional information of a system will increase (i.e., the system will evolve) if many different configurations of the system undergo selection for one or more functions.^[4] Authors of the paper see the potential for these ideas to apply to astrobiology, economics, neuroscience, and more.^[1]

References

1. Ball, Philip (2025-04-02). "Why Everything in the Universe Turns More Complex". Quanta Magazine. Retrieved 2025-04-14.
2. Hazen, Robert M.; Griffin, Patrick L.; Carothers, James M.; Szostak, Jack W. (2007-05-15). "Functional information and the emergence of biocomplexity". Proceedings of the National Academy of Sciences. 104 (suppl_1): 8574–8581. doi:10.1073/pnas.0701744104. PMC 1876432. PMID 17494745.
3. Adami, Christoph; C G, Nitash (2022-05-23). "Emergence of functional information from multivariate correlations". Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences. 380 (2227) 20210250. arXiv:2109.07933. doi:10.1098/rsta.2021.0250. PMID 35599555.
4. Wong, Michael L.; Cleland, Carol E.; Arend, Daniel; Bartlett, Stuart; Cleaves, H. James; Demarest, Heather; Prabhu, Anirudh; Lunine, Jonathan I.; Hazen, Robert M. (2023-10-24). "On the roles of function and selection in evolving systems". Proceedings of the National Academy of Sciences. 120 (43) e2310223120. Bibcode:2023PNAS..12010223W. doi:10.1073/pnas.2310223120. PMC 10614609. PMID 37844243.
5. Pester, Patrick (2023-10-21). "Scientists propose 'missing' law for the evolution of everything in the universe". Space.com. Retrieved 2025-04-14.
6. Dunham, Will (October 16, 2023). "Scientists propose sweeping new law of nature, expanding on evolution". Reuters. Retrieved 2025-04-15.

See also

• Entropy and life
• Second law of thermodynamics
• Specified complexity, a creationist pseudoscientific concept