The above items are what E. Schrödinger coined as ”the construction is different from anything we have yet tested in the physical laboratory” [12]. Consequently, measurements must be designed and carried out with care; the routine methods used for measuring objects from inanimate nature cannot surely be applied to living objects without changing them. In this chapter we discuss some of the relevant terms and notions of physics, differentiating which approximation is appropriate only for physics (mainly electricity and thermodynamics) and, instead, which approximation should be used for biology. Biophysics simply translated the corresponding major terminus technicus words from the theory and practice of physics’ major disciplines, mainly from electricity, which were worked out for homogeneous, isotropic, structureless metals, and for strictly pair-wise interactions with a single (actually, ’instant’) interaction speed; to the structured, non-homogeneous, non-isotropic, material mixtures and for multiple interaction speeds. Those notions do not always have unchanged meaning, and how much they do, depends on the actual conditions. The precise meaning needs a case-by-case analysis.
A common fallacy in biology is that physics cannot underpin the operation of living matter, citing E. Schrödinger. However, the claim falsifies his opinion by omitting the most essential word ’ordinary’. Scrödinger wanted to emphasize the opposite: there is no new force (no unknown new interaction), only studying living matter needs different testing methods in the physical laboratory. He suggested to answer the question ”Is life based on the laws of physics?” affirmatively, but expected to discover the appropriate forms of physical laws describing the ’non-ordinary’ (in our reading: non-disciplinary) behavior of living matter. No doubt, the basic notions and terms must be interpreted precisely for living matter, much beyond the level we used to at college level. However, after that reinterpretation, we can interpret features of living matter, although we need a more careful, many-disciplinary analysis to do so. We must use the appropriate abstractions and approximations for the phenomena, depending on the level needed in the given cooperation of objects and interactions.
The physical models consider infinitely large volumes, surfaces, distances; furthermore, and most importantly: instant interactions. Is the cell large enough to consider it infinitely large (at least on the scale using ion’s size); that is to apply laws of science derived for the abstraction ’infinitely large’? When working with charge, we know that charge is quantized, while the macroscopic quantities voltage and current are continuous (derivable). Do cells contain a sufficient number of charge carriers to apply macroscopic notions? Do the thousands of times smaller ion channels transfer enough charge to speak about well-defined current? When a couple of ions are transferred through an ion channel, do they change significantly the potential that accelerates them?
Life, including the brain’s operation, is dynamic. As Schrödinger formulated, the ”construction of living matter” differs from the one science used to test in its labs. The scientific abstraction based on ”states” (i.e., on instant changes) fails for the case of biology, where ”processes” happen (i.e., the changes are obviously much slower). The commonly used measuring methods such as clamping, patching, and freezing, reduce the life to states (and correspondingly, the related theories describe states with perturbance [90]). On the one side, this technology fixes the cell at some well-defined static state and enables one to observe a static anatomic picture of the cell. On the other, it eliminates the dynamic processes, i.e., hides for forever the essence of the life that the cell exists in a continuous change governed by laws of motion. Those methods stop the processes for studying them, in this way killing their dynamicity to be measured. It was forgotten that using feedback for stabilizing an autonomously working electrical system means introducing foreign currents and this way falsifying its operation.
Furthermore, it is hazardous to introduce technically (and incorrectly) derived and misinterpreted macroscopic features and interpret them as fundamental electrical notions. In general, instead of understanding and developing the correct scientific base of the operation, saying that science cannot describe it. The idea of conductance has been introduced to neurophysiology almost a century ago. It was taken from physics, where the notion was derived for metals (conductors, instead of electrolytes). Since then, its original interpretation has been forgotten, and today (in contrast with physics), fundamentally due to the wrong concept of ’equivalent circuit’) it has become a primary entity for describing electrical characteristics of biological cells. We explain how the right physics background enables us to discover wrong physical models and misinterpreted notions of physics in neurophysiology; furthermore, how the right interpretation opens the way to the correct interpretation of neuronal information. We set up an abstract electrical model of neuronal operation.
We derive the needed ’non-ordinary laws’, which are derived by using the same first principles as the ’ordinary laws’, but are abstracted for the approximations valid for living matter. As we discuss, those ’ordinary’ laws were derived for strictly pair-wise interactions at very high speeds. In biology, we can observe interactions at million times smaller speed, in inhomogeneous, non-isotropic, structured material. Biology does not have the conditions for which the ordinary laws of physics were derived. We show that the ordinary laws are also the result of approximations (including omissions) and by using the appropriate approximations for the biological cases we can derive those ’non-ordinary’ laws of physics. Which laws are more complex to derive and need joining different disciplines, furthermore, we must use several stages (with approximations changing from stage by stage) instead of one single stage in the case of the ’ordinary’ laws. However, all laws follow the same principles.
Biology, and especially neuronal operation, produces examples where wrong omissions in complex processes results in absolutely wrong results. In those cases some initial resemblance between our theoretical predictions and our phenomena exist, but the success in simple cases provides no guarantee that the model was appropriate: ”the success of the equations is no evidence in favour of the mechanism” [9]. Several theories can describe the same phenomenon with the required accuracy. We also show in the section about the finite interaction speeds that the mostly known laws (from Newton, Coulomb, Kirchoff, etc.) are also approximations. They have their range of validity, although it is often forgotten.
One such neuralgic point of omissions and approximations is the vastly different interaction speeds; furthermore, that where the speed is considered at all, the same speed is assumed for all interactions. The laws are abstract also in the sense that, say, the objects in the laws of physics have either mass or electric charge, but not both. It is the researcher’s task to decide which combination of laws can be applied to the given condition. For example, one can assume in most cases that the speeds sum up linearly, except at very high speeds. Biology provides excellent case studies where different interactions shape the phenomenon and special care must be exercised. We give a short review of history and kinds of interaction speeds.
Another point is that science started with the assumption that the non-living matter is continuous, although it was early discovered that there are smallest pieces of that matter. When we approached that size, we experienced that different subsets of science laws describe that matter and the atoms they contain; in is one of the hardest tasks to establish relations between those subsets. Again, we used abstractions that the continuous matter is infinitely large and that the isolated atoms are infinitely far from each other and from the external world. We also experienced the semi-infinite cases, and studied the behavior of surfaces and interfaces; which, again is different from both that of the atoms and their large masses. Given that biological objects are between those microscopic and macroscopic sizes, and they are surrounded by surfaces, we must be prepared that no simple rules describe their behavior.
Neuronal operation is at the boundary where sometimes, in the same phenomenon, one interaction can be interpreted at macroscopic level, some another must already be interpreted at microscopic level. Furthermore, a series of stages (instead of a single state) and processes (instead of stages) describe the subject under study. Given the vital role of charge and current in neuronal operation, we give their precise interpretation. Furthermore, we must consider that the processes happen in a finite volume, ”within the spatial boundary”. Special emphasis is given to the true interpretation of conductance, one of the central terms in biology.