Moreno

Then it is an insufficient condition by itself to work as PM. I also have a question about Maxwell's demon. In a classical example it is described as a mechanism which without energy looses gathers hot molecules in one reservoir and cold molecules in the other. But what happens to entropy of these two reservoirs in comparison to initial state? Since entropy is an additive value we could say entropy of initial reservoir was=X, and after it was divided in two and molecules were sorted by their speed, what would be entropy of Y+Z, the same as X in total or larger?

As I said, if during some energy conversion process entropy in the universe in total will increase, our ability to perform useful work will diminish. Therefore in order for perpetuum mobile of the second kind to function increase of entropy in some place should be compensated by its decrease somewhere else (and simultaneously!) for exactly the same value. I'm not sure particularly about the cylinder you described, but think that if cylinder looses thermal energy to the environment it would need to draw the same amount of thermal energy from environment to compensate looses. So, you describe situation when entropy increases in total, which doesn't suit a hypothetical conditions I mentioned.

I didn't claim I'm going to beat the second law. I said if we believe in current second law definition it seems like we may construct (in theory!) a perpetuum mobile of the second kind which works WITHIN the second law. What is concerning to some particular example, it's pretty difficult to do because we need to agree what is a truly closed system and find it in nature. The Earth may not be a truly closed system and its extremely difficult to isolate any system from surrounding environment. But let try. For example there is a Belousov chemical reactions which seem to be oscillation of some chemical solution from one chemical state to another and back. https://en.wikipedia.org/wiki/Belousov%E2%80%93Zhabotinsky_reaction I have no idea if such type of oscillations could be truly eternal and non-dissipative. But if they do, let imagine a chemical system which exist in thermodynamic equilibrium with surrounding environment. Such system would be divided in two main parts which experience oscillations between these two parts. When one part of the system transfers from amorphous to crystalline state entropy reduces and it cools down. It shrinks in size and absorbs heat from surrounding environment. The other part of the system in the same time experience opposite transition - it transfers from crystalline to amorphous state, releases heat, increases in size and capable produce some useful work, for example, to push a piston. After work is done heat released to environment. However, entire system constantly draws the same amount of heat from environment as it releases. So, it exist in thermodynamic equilibrium with nature. If according to second law there could exist some processes which remain total amount of entropy in universe unchanged (I assume that under word "process" they also mean conversion of some type of energy into some kind of a useful work), and we could build some engine which harnesses such type of process, then our ability to perform some useful work should never diminish. And we would have a perpetuum mobile. If our ability to perform work diminishes then it means entropy increases during the process. But the second law doesn't state it is the only outcome possible. This one article mentions some similar ides (though not necessarily the same). http://phys.org/news/2014-09-physicists-zero-friction-quantum.html

How?

It is commonly assumed that perpetuum mobile of the second kind or maxwell's demon suppose to violate the second law of thermodynamics. And the second law of thermodynamics claims that: "In every real process the sum of the entropies of all participant bodies is increased. In the idealized limiting case of a reversible process, the sum remains unchanged." (Wikipedia) However, does this "idealized limiting case", as they said, contradicts to nature's laws? If not, then doesn't it means that in theory perpetuum mobile of the second kind could be created? Let assume we have eternal non-dissipative oscillations in some system during which entropy increases in one part of a system and decreases for exactly the same value in the other part. It happens constantly during oscillations. Total amount of entropy in the universe is unaffected by this system. Thus we have a perfectly reversible process. Then during entropy reduction in one part of the system a useful work could be performed each time.

In my understanding any democracy and freedom could exist until majority of people could protect them with weapons in their hands. Will technological changes (especially development of weapons and all-pervasive spying systems) ultimately make free society impossible? Then we have to admit that technological progress slows down social progress? Isn't it paradoxical? I mean what regular people in some modern civilized country (who are armed with non-automatic guns at best) could do against stealth bombers, nuclear bombs, submarines etc. In the nearest future there will be robotic military and police systems and spying cameras at every corner. Is there some way to reverse this negative tendency?

Wondering, how some posters ignored what topic starter wrote. I'm afraid that cooperatives will never be able to become a dominant form of property without help of government for a two simple reasons: people who want to create them will always miss capital to create them even if they will join their small money savings. Neither they would be able to compete with already established giant corporations/monopolies. Total price of production means/commercial property is a way larger than total price of personal property of regular people (small employees) and especially their savings. Capital has tendency to concentration. Therefore there is a vicious circle: majority of people have modest incomes because they are not business (co)owners and they will never be able to become an equal co-owners because their modest incomes will not allow them to purchase a share large enough. Furthermore I do not understand who would want to sell a really profitable business or even its shares. Therefore the idea you propose would require some nation-wide scale efforts and political changes. "JohnB" wrote: What principal difference does it make whether a manager is responsible before a few business owners (director's board) or many small co-owners (cooperative)? Cooperative workers could become disappointed in manager and decide not to re-elect him/her but a few business owners could do the same.