(source) 
Ludwig Eduard Boltzmann
(20 Feb 1844  5 Sep 1906)

Science Quotes by Ludwig Eduard Boltzmann (8 quotes)
A closer look at the course followed by developing theory reveals for a start that it is by no means as continuous as one might expect, but full of breaks and at least apparently not along the shortest logical path. Certain methods often afforded the most handsome results only the other day, and many might well have thought that the development of science to infinity would consist in no more than their constant application. Instead, on the contrary, they suddenly reveal themselves as exhausted and the attempt is made to find other quite disparate methods. In that event there may develop a struggle between the followers of the old methods and those of the newer ones. The former's point of view will be termed by their opponents as outdated and outworn, while its holders in turn belittle the innovators as corrupters of true classical science.
— Ludwig Eduard Boltzmann
Available energy is the main object at stake in the struggle for existence and the evolution of the world.
— Ludwig Eduard Boltzmann
I wept when I saw the color of the sea—how can a mere color make one cry? Or moonlight, or the luminescence of the sea in a pitch black night? … But if there is one thing which is more worthy of our admiration than natural beauty, it is the art of men who have conquered this neverending sea so Fully in a struggle that has been going since the time of the Phoenicians.
— Ludwig Eduard Boltzmann
S = k log Ω
Carved above his name on his tombstone in the Zentralfriedhof in Vienna.
Carved above his name on his tombstone in the Zentralfriedhof in Vienna.
— Ludwig Eduard Boltzmann
Since a given system can never of its own accord go over into another equally probable state but into a more probable one, it is likewise impossible to construct a system of bodies that after traversing various states returns periodically to its original state, that is a perpetual motion machine.
— Ludwig Eduard Boltzmann
The most ordinary things are to philosophy a source of insoluble puzzles. In order to explain our perceptions it constructs the concept of matter and then finds matter quite useless either for itself having or for causing perceptions in a mind. With infinite ingenuity it constructs a concept of space or time and then finds it absolutely impossible that there be objects in this space or that processes occur during this time ... The source of this kind of logic lies in excessive confidence in the socalled laws of thought.
— Ludwig Eduard Boltzmann
The stars bend like slaves to laws not decreed for them by human intelligence, but gleaned from them.
— Ludwig Eduard Boltzmann
We must make the following remark: a proof, that after a certain time t_{1}, the spheres must necessarily be mixed uniformly, whatever may be the initial distribution of states, cannot be given. This is in fact a consequence of probability theory, for any nonuniform distribution of states, no matter how improbable it may be, is still not absolutely impossible. Indeed it is clear that any individual uniform distribution, which might arise after a certain time from some particular initial state, is just as improbable as an individual nonuniform distribution; just as in the game of Lotto, any individual set of five numbers is as improbable as the set 1, 2, 3, 4, 5. It is only because there are many more uniform distributions than nonuniform ones that the distribution of states will become uniform in the course of time. One therefore cannot prove that, whatever may be the positions and velocities of the spheres at the beginning, the distributions must become uniform after a long time; rather one can only prove that infinitely many more initial states will lead to a uniform one after a definite length of time than to a nonuniform one. Loschmidt's theorem tells us only about initial states which actually lead to a very nonuniform distribution of states after a certain time t_{1}; but it does not prove that there are not infinitely many more initial conditions that will lead to a uniform distribution after the same time. On the contrary, it follows from the theorem itself that, since there are infinitely many more uniform distributions, the number of states which lead to uniform distributions after a certain time t_{1}, is much greater than the number that leads to nonuniform ones, and the latter are the ones that must be chosen, according to Loschmidt, in order to obtain a nonuniform distribution at t_{1}.
— Ludwig Eduard Boltzmann
Quotes by others about Ludwig Eduard Boltzmann (4)
Qu'une goutee de vin tombe dans un verre d'eau; quelle que soit la loi du movement interne du liquide, nous verrons bientôt se colorer d'une teinte rose uniforme et à partir de ce moment on aura beau agiter le vase, le vin et l'eau ne partaîtront plus pouvoir se séparer. Tout cela, Maxwell et Boltzmann l'ont expliqué, mais celui qui l'a vu plus nettement, dans un livre trop peu lu parce qu'il est difficile à lire, c'est Gibbs dans ses principes de la Mécanique Statistique.
Let a drop of wine fall into a glass of water; whatever be the law that governs the internal movement of the liquid, we will soon see it tint itself uniformly pink and from th at moment on, however we may agitate the vessel, it appears that the wine and water can separate no more. All this, Maxwell and Boltzmann have explained, but the one who saw it in the cleanest way, in a book that is too little read because it is difficult to read, is Gibbs, in his Principles of Statistical Mechanics.
Let a drop of wine fall into a glass of water; whatever be the law that governs the internal movement of the liquid, we will soon see it tint itself uniformly pink and from th at moment on, however we may agitate the vessel, it appears that the wine and water can separate no more. All this, Maxwell and Boltzmann have explained, but the one who saw it in the cleanest way, in a book that is too little read because it is difficult to read, is Gibbs, in his Principles of Statistical Mechanics.
It is a remarkable fact that the second law of thermodynamics has played in the history of science a fundamental role far beyond its original scope. Suffice it to mention Boltzmann’s work on kinetic theory, Planck’s discovery of quantum theory or Einstein’s theory of spontaneous emission, which were all based on the second law of thermodynamics.
Boltzmann was both a wizard of a mathematician and a physicist of international renown. The magnitude of his output of scientific papers was positively unnerving. He would publish two, three, sometimes four monographs a year; each one was forbiddingly dense, festooned with mathematics, and as much as a hundred pages in length.
Newton was the greatest creative genius physics has ever seen. None of the other candidates for the superlative (Einstein, Maxwell, Boltzmann, Gibbs, and Feynman) has matched Newton’s combined achievements as theoretician, experimentalist, and mathematician. … If you were to become a time traveler and meet Newton on a trip back to the seventeenth century, you might find him something like the performer who first exasperates everyone in sight and then goes on stage and sings like an angel.
See also:
 20 Feb  short biography, births, deaths and events on date of Boltzmann's birth.
 Boltzmann's Atom: The Great Debate That Launched A Revolution In Physics, by David Lindley.  book suggestion.