In the Beginning was Information
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work is <strong>the</strong>oretically impossible. This asymmetry is a primary result of <strong>the</strong>second law. <strong>In</strong> addition, <strong>the</strong> second law asserts that closed systems tendtowards a state where <strong>the</strong> usable energy is a minimum, and <strong>the</strong> entropybecomes a maximum. The change in <strong>the</strong> amount of entropy indicateswhe<strong>the</strong>r a process is reversible or not. The better a process can prevent anincrease in entropy, <strong>the</strong> more useful energy can be produced. Potential andkinetic energy, as well as electrical energy, can be arbitrarily convertedinto one ano<strong>the</strong>r in such a way that <strong>the</strong> process is very nearly completelyreversible and can thus produce a maximum amount of useful work.On <strong>the</strong> o<strong>the</strong>r hand, heat energy can only be partially converted intomechanical work or into some o<strong>the</strong>r form of energy. It is impossible toconvert more than a certain fraction of <strong>the</strong> supplied heat energy, as givenby <strong>the</strong> formula Ë = (T 2 - T 1 )/T 2 for an ideal Carnot machine (a reversibleCarnot cycle; see also paragraph 2.5). This <strong>the</strong>rmodynamically possibleamount of useful energy is known by a distinctive name, exergy. The factthat it is impossible to obtain more work from a heat engine than allowedby Ë C follows directly from <strong>the</strong> second law.Living organisms have a greater efficiency (= useful mechanical workobtained from a given energy input) than <strong>the</strong> maximum <strong>the</strong>rmal efficiencyallowed by <strong>the</strong> second law. This does not contradict this natural law, butindicates that <strong>the</strong> Creator has endowed body muscles with <strong>the</strong> capacity toconvert chemical energy directly into mechanical work, and do so muchmore efficiently than ordinary heat engines can.Conclusion: The law of entropy precludes all events which might lead to adecrease in entropy, even while obeying <strong>the</strong> energy law. Entropy thusreveals itself to be one of <strong>the</strong> most important and most remarkable conceptsof physics.Entropy and disorder? <strong>In</strong> countless publications examples are givenwhich illustrate that when <strong>the</strong> entropy of a system increases, <strong>the</strong> amountof disorder also increases; in o<strong>the</strong>r words, <strong>the</strong> orderliness is diminished.This idea has unfortunately also been extended to biological systems. Thefollowing arguments refute such a view:– Biological processes take place in open systems, and are not closed. Thesecond law allows a decrease in entropy as long as <strong>the</strong>re is a correspondingincrease in entropy in <strong>the</strong> environment. But what is completelyprecluded is that <strong>the</strong> overall amount of entropy could be diminished.– There can be no generally valid relationship between entropy and disorder,because entropy is a physical quantity which can be formulatedexactly, but <strong>the</strong>re is no exact formulation for disorder. The presentauthor attempted a classification of <strong>the</strong> order concept in [G5], and differentkinds of order are depicted in Figure 43.225