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Introduction and Physical Background Biological Impacts and Consciousness Research

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Introduction and Physical Background

In the trial of explaining "life", biophysics is confined to two basic quantities, that is matter and energy. On the one hand this avoids a lot of confusion with definitions of, say, body, flesh, mind, spirit, consciousness, or soul. On the other hand, these two terms matter and energy may not suffice to describe the rather complicated phenomena that we call „life„. However, by comparing molecular biology ( which is the basis of our present understanding of life)  with  modern physics, one finds an alternative and deeper understanding of life by distinguishing between (1) the description in terms of molecular reactions of  genes, hormones , receptors, ...., and (2) the biophysical approach in terms of the energy distribution over the whole body. 
 

Fig.1 In order to understand the properties of matter, not only the material content is decisive but also the content and distribution of the energy over matter. Examples are ice and water or relaxed and flexed muscles.

Actually, even the properties of dead materials are not understandable by the investigation of  matter alone. As an example take the case of water and ice. Both consist of the molecules H2O. However the properties are quite different. This difference is not based on different matter, but on different energy content which leads to different entropy of the aggregates. 
The entropy indicates how the available energy is distributed over a definite arrangement of matter. It tells us, for instance, how photons (quanta of electromagnetic energy ) are occupying the „phase space„ of the system under investigation. Under „phase space„ the physicist understands not only the spatial space but also the „momentum space„ which takes into account the possibilities of taking up particles of different quantum energy and different direction of propagation. The thermodynamical probability W accounts for all the numbers of the different ways to distribute particles (like photons) to the different available quantum states of their energy ( Fay, 1965) ¹. 
Take a definite quantum energy e and count the number N(e) of different ways to assign to the present n(e) particles of this energy e the C(e) available phase space cells in a given volume V. Then multiply all these numbers N(e) for all the different energy values e₁, e₂, e₃, ..... in order to get the „thermodynamical probability W. The entropy S is defined as S = k ln W, where k is Boltzmann`s constant (k = 1.3805  10^-16 erg/K,  K representing the absolute temperature in „Kelvin„) and ln W is the natural logarithm of W. 
W and S are functions of the volume V under consideration, and of the numbers N(*) and C(*). It turns out that the entropy (or the thermodynamical probability W) is the most essential quantity in macroscopic physics, since it is responsible for the dynamics of matter, e.g. the course of chemical reactions, degradation of  structures, particle flow, and distribution of mechanical or electrical potentials (pressure, electrical or magnetic  forces).  Even the arrow of time is based on the „second law of thermodynamics„ which states that the entropy S (or W) always takes its maximum  under the boundary conditions of the system under study. Roughly speaking,  this means that every system displays the tendency to arrive at the most probable state where the energy is distributed in the most uniform way. 
We have to distinguish between closed and open systems.  Dead matter belongs generally to closed systems where  the external „heat bath„ at constant temperature provides at any instant that as much heat flows into this inactive matter as is going out from it. As a result closed systems have at equilibrium the temperature of their surroundings. Open systems, on the other hand, do not only exchange heat with the external world but also „signals„, e.g. special electromagnetic waves or matter. Since living systems are exposed to essential signals such as sun rays („photosynthesis„) or material food, they are certainly not „ideal„ closed systems. On the contrary, we will see later in this paper that they are to some extent „ideal open sytems„.
For understanding open systems (like living ones) it is useful to compare them with closed ones in order to get an idea of the most significant differences of animated and unanimated matter. In a closed system the maximum entropy has to follow the rather basic condition that the flow of heat energy between surroundings and the system under study is always balanced. This condition provides a stationary equilibrium state. Thus, the entropy of ice, for example, has its maximum value under the condition that the temperature of the external world is low enough for taking up just as small an amount of heat from ice as it gives back. Again, at higher temperatures above 0o Celsius the entropy of water arrives at a maximum under just the same constraint that the heat production of water is compensated by the inflow of heat from the surroundings. Therefore, ice and water are closed systems. Consequently, the common property of both is the maximum of entropy under the constraint of energy conservation. The essential difference between ice and water, then, has its origin simply in the different energy densities. Maximum entropy in closed systems requires a definite temperature T as well as a definite occupation of the different energy levels e₁, e₂,  e₃,....  with photons of energy e₁, e₂, e₃, ....known as Bose-Einstein - statistics (or, in the optical range, Boltzmann-distribution, n( e) µ exp (- e/kT)). It states that with increasing temperature T, the number n( e) of (thermal) photons increase, and with increasing quantum energy e of the excited states, the number of photons of energy  e drops down exponentially. As a consequence, „dead„ material displays in general no chemical reactivity, simply because there are not enough photons available to trigger internal reactions of high activation energy Ea = e = h u. However, every chemical reaction takes place in such a way that at least one of the reaction partners has to be excited by a photon of suitable energy Ea in order to build up a transition state complex that works as the necessary first step of chemical reactions (Lehninger, 1975) ². (Fig.2). 
 

Fig.2  Every chemical reaction takes place if, and only if, at least one of the reacting compounds is excited by a photon of suitable activation energy Ea= hn, where n  is the frequency of the activating photon, and h is Planck`s constant. This means that (1) without photons chemical reactions are not possible and (2) the distribution of photons regulates the chemical reactivity in non-living and living matter.

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