History of Biological Physics
The ‘complementarity principle’ of quantum mechanics says that a particle also has wave-like features. In 1932 Niels Bohr, who made foundational contributions to understanding the atomic structure, suggested a similar principle in biology in his lecture “Light and life”. In his opinion understanding the mechanism of life means taking a living organism apart and hence destroying the phenomenon set out to study. This paradox can effectively be summarised as the end of reductionism, which served science so well in previous centuries. Max Dellbrück was fascinated by these thoughts and dedicated his career to developing the mechanisms of gene regulation in the 1940s prior to the discovery of the DNA structure in 1953 (in part due to another physicist, Francis Crick). Physicist Erwin Schrödinger, who made seminal contributions to quantum mechanics, also began to ponder biology. In 1943 he gave the famous lecture ‘What is life?”, which later was published as a book. In this lecture Erwin wondered about fundamental questions in biology, such as how genetic information ought to be encoded (‘aperiodic crystal’) and how order emerges, emphasising the role of ‘negative entropy’ (free energy). Similar to Niels Bohr he also wondered whether new physical laws are required to understand living systems. In a sense, the answer turned out to be ‘no’. However, how life emerges from physical and chemical principles (i.e. the ‘origin of life’) is still an open question. A new kind of physics may nevertheless be required, likely based on stochastic thermodynamics and information theory. These fundamental issues aside, what is modern biological physics about?
Biological physics is a relatively new discipline of physics. While experimental biological physics has produced many new measurement technologies for biological research, it often investigates biological systems under highly controlled conditions, e.g. by using well-defined nano-patterned environments, by conducting force measurements, or by studying well-controlled in vitro systems. Theoretical biological physics is on equal footing with experimental biological physics in the tradition of other physics disciplines. Some work in theoretical biological physics has focused on ‘modelling’ one data set or organism a time, or on making very specific predictions to be tested by very specific experiments, e.g. in terms of changing model parameters to mimic mutants. However, theoretical biological physics is much more; it constitutes a powerful framework for thinking about biological problems. Such thinking ultimately aims to produce ‘leaps of understanding’, e.g. by deducing general, universal principles, applicable to many different biological systems or across multiple length or time scales. These are truly challenging tasks as biological systems are complex – they are small, open, coupled, nonlinear, driven, noisy, and operate at finite temperatures. In short, they are alive!
