Ludwig Boltzmann Quotes

“We note that occasionally the remark is made that what Carnot called heat was actually entropy, which is conserved in his cycle. Although it would be preposterous to say that Carnot discovered entropy, we may understand why his argument worked and why Clausius and Thomson were able to rescue his cycle and incorporate it in the new discipline. Essentially he saw that there was something that was conserved in reversible processes; this was not heat or caloric, however, but what was later called entropy.”
― Carlo Cercignani, Ludwig Boltzmann: The Man Who Trusted Atoms

“Entropy derives from the Greek “conversion”, “mutation”, “evolution”, but also “confusion” and “shame” (this latter meaning one finds in the writings of Hippocrates in the form ).”
― Carlo Cercignani, Ludwig Boltzmann: The Man Who Trusted Atoms

“In 1877 he published his paper “Probabilistic foundations of heat theory”, in which he formulated what Einstein later called the Boltzmann principle; the interpretation of the concept of entropy as a mathematically well-defined measure of what one can call the “disorder” of atoms, which had already appeared in his work of 1872, is here extended and becomes a general statement.”
― Carlo Cercignani, Ludwig Boltzmann: The Man Who Trusted Atoms

“heat “always shows a tendency to equalize temperature differences and therefore to pass from hotter to colder bodies” [15]. A”
― Carlo Cercignani, Ludwig Boltzmann: The Man Who Trusted Atoms

“Here Boltzmann is referring to the fact that an atom cannot be a simple object, as was amply known in his time from spectroscopy. It was the study of this structure that paved the way to the theory of elementary particles in the twentieth century. These are the bricks from which one builds atoms and may derive a force between atoms of the kind imagined by Boscovich.”
― Carlo Cercignani, Ludwig Boltzmann: The Man Who Trusted Atoms

“For a long time the celebrated theory of Boscovich was the ideal of physicists. […] If this theory were to hold good for all phenomena, we should be still a long way off what Faust’s famulus hoped to attain, viz. to know everything. But the difficulty […] would be only a quantitative one; nature would be a difficult problem, but not a mystery for the human mind. […] this simple conception of Boscovich is refuted in every branch of science, the Theory of Gases not excepted. The assumption that the gas-molecules are aggregates of material points, in the sense of Boscovich, does not agree with facts.”
― Carlo Cercignani, Ludwig Boltzmann: The Man Who Trusted Atoms

“Thus, says Helmholtz [19], we do not try to construct machines that perform the thousands of acts typical of a man, but rather require that one machine performs a single act and replaces thousands of men.”
― Carlo Cercignani, Ludwig Boltzmann: The Man Who Trusted Atoms

“he stressed that the main feature of science is economy of thought;”
― Carlo Cercignani, Ludwig Boltzmann: The Man Who Trusted Atoms

“In the description of matter as a collection of molecules instead of a continuum, questions related to reversibility are presented for the first time in the invention, almost as a joke, of what is now known as “Maxwell’s demon”.”
― Carlo Cercignani, Ludwig Boltzmann: The Man Who Trusted Atoms

“It was during his career as a military surgeon that he published his most celebrated essay on “The conservation of force”, where “force” had the meaning, then common, of “energy”. There is no doubt that this essay imparted a very great impulse to the problem of understanding the role and meaning of this basic principle of physics. In particular, Helmholtz clarified the assumptions that have to be made about a mechanical system in order to ensure that energy is conserved. As a result of his work the principle of conservation of energy became the unfailing guide to organizing physical facts and theories in a clear scheme.”
― Carlo Cercignani, Ludwig Boltzmann: The Man Who Trusted Atoms

“The Second Law indicates that not all the processes compatible with the First Law can actually occur. Whereas one can easily perform work to heat up the system, it is not always enough to supply heat to increase the mechanical energy. At least two heat sources at different temperatures are needed, as shown by Carnot’s argument (sometimes one of the sources may be naturally supplied by the environment). Essentially the Second Law states that heat can never pass from a colder to a warmer body without some other related change occurring at the same time (see also the next chapter). The new ideas were propagated in a rapid fashion thanks to the lively and elegant exposition by Thomson [17]. The conservation of energy in the atomic model found its final treatment in the hands of Hermann von Helmholtz (1821–94), who, like Mayer, started from physiological considerations, and about whom we spoke in detail in the previous chapter. In his fundamental work of 1847 [18] he explicitly introduced the concept of potential energy.”
― Carlo Cercignani, Ludwig Boltzmann: The Man Who Trusted Atoms

“The First Law simply states that the change in total energy equals the work performed on, plus the heat supplied to, the system (measured in suitable units).”
― Carlo Cercignani, Ludwig Boltzmann: The Man Who Trusted Atoms

“The First Law starts from the fact that in any physical system there are two kinds of energy (for simplicity, we ignore the possible presence of electric and magnetic fields), mechanical and thermal. Their sum may change because one performs work on the system or supplies heat to the system.”
― Carlo Cercignani, Ludwig Boltzmann: The Man Who Trusted Atoms

“The consequences of Thomson’s Principle of Dissipation were elaborated by Hermann von Helmholtz, who two years later described the “heat death” of the universe, the consequence of the transformation of all energy into heat [14].”
― Carlo Cercignani, Ludwig Boltzmann: The Man Who Trusted Atoms

“The conservation of energy in the atomic model found its final treatment in the hands of Hermann von Helmholtz (1821–94), who, like Mayer, started from physiological considerations, and about whom we spoke in detail in the previous chapter. In his fundamental work of 1847 [18] he explicitly introduced the concept of potential energy.”
― Carlo Cercignani, Ludwig Boltzmann: The Man Who Trusted Atoms

“Now up to the end of the eighteenth century, notably in the work of chemists, heat was treated as a substance, named caloric by the great French chemist Antoine Laurent Lavoisier (1743–1794), who made the first attempt to introduce the methods and concepts of physics laid down by Galileo and Newton into chemistry.”
― Carlo Cercignani, Ludwig Boltzmann: The Man Who Trusted Atoms

“These are presumably the thoughts that made him restless.”
― Carlo Cercignani, Ludwig Boltzmann: The Man Who Trusted Atoms

“1.3 Restlessness”
― Carlo Cercignani, Ludwig Boltzmann: The Man Who Trusted Atoms

“Rather than probability, one can speak of a measure of the disorder of the atoms, because the equivalent disordered states (for a given macroscopic state) are very many and the probability that one of them occurs is extremely high. We shall discuss this paper in detail in Chapter 6.”
― Carlo Cercignani, Ludwig Boltzmann: The Man Who Trusted Atoms

“About this unpleasant situation Boltzmann wrote: “I hate this continuous secret battle; I know much better how to integrate than how to intrigue.”
― Carlo Cercignani, Ludwig Boltzmann: The Man Who Trusted Atoms

“Whenever he had to leave her, Boltzmann, who was tender-hearted, was not able to hold back his tears.”
― Carlo Cercignani, Ludwig Boltzmann: The Man Who Trusted Atoms

“At first he did not realize what he had accomplished; he thought that he had remained within the boundaries of mechanics, that he was computing actual numbers of molecules, without realizing how much probability was involved.”
― Carlo Cercignani, Ludwig Boltzmann: The Man Who Trusted Atoms

“There is no mechanical impossibility, it is merely the fact that there are so many more possible positions of the various powder grains that will give a grey appearance, as compared to the much smaller number of configurations in which the grains are well ordered.”
― Carlo Cercignani, Ludwig Boltzmann: The Man Who Trusted Atoms

“In the same paper Boltzmann was able to derive a proof of the irreversibility of macroscopic phenomena. It is the difference of scale between the objects that we observe in everyday life on the one hand, and molecules on the other hand, which explains this irreversibility through the laws of probability.”
― Carlo Cercignani, Ludwig Boltzmann: The Man Who Trusted Atoms

“The night of his birth marked the passage from Shrove Tuesday to Ash Wednesday and Boltzmann used to say that his birth date explained why his temper could suddenly change from great happiness to deep depression.”
― Carlo Cercignani, Ludwig Boltzmann: The Man Who Trusted Atoms

“What we can do is to establish a bridge between the various levels in order to form a coherent picture; the whole of Boltzmann’s work is a masterpiece of this procedure, i.e. how to construct, starting from atoms, a description that explains everyday life.”
― Carlo Cercignani, Ludwig Boltzmann: The Man Who Trusted Atoms

“There are hierarchies of structures, and new concepts arise at each level.”
― Carlo Cercignani, Ludwig Boltzmann: The Man Who Trusted Atoms