In the Beginning was Information
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Conservation <strong>the</strong>orems: The following description applies to thisgroup of laws: A certain number, given in a suitable unit of measurement,can be computed at a specific moment. If this number isrecomputed later after many changes may have occurred in nature,its value is unchanged. The best-known law in this category is <strong>the</strong>law of <strong>the</strong> conservation of energy. This is <strong>the</strong> most abstract and <strong>the</strong>most difficult of all <strong>the</strong> conservation laws, but at <strong>the</strong> same time it is<strong>the</strong> most useful one, since it is used most frequently. It is more difficultto understand than <strong>the</strong> laws about <strong>the</strong> conservation of mass(see footnote 5), of momentum, of rotational moment, or of electricalcharge. One reason is that energy can exist in very many differentforms, like kinetic energy, potential energy, heat, electricalenergy, chemical energy, and nuclear energy. <strong>In</strong> any given process<strong>the</strong> involved energy can be divided amongst <strong>the</strong>se forms in verymany different ways, and a number can <strong>the</strong>n be computed for eachkind of energy. The conservation law now states that <strong>the</strong> sum of all<strong>the</strong>se numbers stays constant irrespective of all <strong>the</strong> conversionsthat took place during <strong>the</strong> time interval concerned. This sum isalways <strong>the</strong> same at any given moment. It is very surprising thatsuch a simple formulation holds for every physical or biologicalsystem, no matter how complex it may be.Equivalence <strong>the</strong>orems: Mass and energy can be seen to be equivalentin terms of Einstein’s famous formula E = m x c 2 . <strong>In</strong> <strong>the</strong> caseof atomic processes of energy conversion (nuclear energy) <strong>the</strong>re isa small loss of mass (called <strong>the</strong> deficit) which releases an equivalentamount of energy according to Einstein’s formula.Directional <strong>the</strong>orems: From experience in this world we knowthat numerous events proceed in one sense only. A dropped cupwill break. The converse event, namely that <strong>the</strong> cup will put itselftoge<strong>the</strong>r and jump back into our hand, never happens, howeverlong we may wait. When a stone is thrown into a dam, concentricwaves move outwards on <strong>the</strong> surface of <strong>the</strong> water. This process canbe described ma<strong>the</strong>matically, and <strong>the</strong> resulting equations are equallyvalid for outward moving waves and for <strong>the</strong> imaginary case ifsmall waves should start from <strong>the</strong> edge and move concentricallyinwards, becoming larger as <strong>the</strong>y do so. This converse process hasnever been observed, although <strong>the</strong> first event can be repeated asoften as we like.37