
Examples of open, closed, and isolated systems; the ignorant person, in respect to Clausius, will incorrectly often assert that the first law applies to ALL three systems, but that the second law and or entropy "only applies" to isolated and or closed systems.

Examples of open, closed, and isolated systems; the ignorant person, in respect to Clausius, will incorrectly often assert that the first law applies to ALL three systems, but that the second law and or entropy "only applies" to isolated and or closed systems.

In hmolscience, entropy only applies (or second law only applies), as compared to “entropy applies to everything” (or second law applies to everything) view, is an overly-common argument from ignorance, generally made by people to don't read Clausius, i.e. the original source definition of entropy and the second law, according to which it is fallaciously asserted that entropy and or the second law, depending on the level of confusion of the asserter, does apply to "isolated" and or "closed" systems (the asserter often convolutes and confuses these two system types likewise) , but does NOT apply to "open" systems.

Overview
The "entropy only applies" dictum, which is equivalent to the synonymously ignorant statement "heat only applies", arises in the uneducated mind, generally in publications dealing with "life", i.e. powered CHNOPS+# existence states, or "evolution", owing to the assumed belief that entropy means disorder; in equation form:

a variant of which Helmholtz (1882) was the first (Ѻ) to state, albeit "in context"; the "in context" aspect, however, is the crucial part the naive expositor tends to unaware of. Correctly, energy and entropy apply to EVERY body or system in the universe. This, in short, is a more exact and detailed statement of Boerhaave's law, namely: ALL bodies expand when heated. Those in the know, e.g. Gibbs, as shown below, understand this as a matter of fact.

“The comprehension of the laws which govern ANY material system is greatly facilitated by considering the energy and entropy of the system in the various states of which it is capable. As the difference of the values of the energy for any two states represents the combined amount of work and heat received or yielded by the system when it is brought from one state to the other, and the difference of entropy is the limit of all the possible values of the integral ∫ dQ/T, dQ denoting the element of the heat received from external sources, and T the temperature of the part of the system receiving it, the varying values of the energy and entropy characterize in all that is essential the effects producible by the system in passing from one state to another.”
— Willard Gibbs (1876), On the Equilibrium of Heterogeneous Substances


An example of a van't Hoff equilibrium box style semi-open system, with boundaries semi-permeable to certain chemical species, but impermeable to other species; which is the general type of system, e.g. social systems, of interest when humans are subject of discussion, in regards to energy and entropy.

An example of a van't Hoff equilibrium box style semi-open system, with boundaries semi-permeable to certain chemical species, but impermeable to other species; which is the general type of system, e.g. social systems, of interest when humans are subject of discussion, in regards to energy and entropy.

The general root of the confusion is that people see themselves as an ordered structure, aka a "low entropy state" in thermodynamic speak, hence the blanketed Clausius statement "entropy of the universe tends to a maximum" means to the uneducated person that "disorder of the system tends to a maximum"; according, to resolve this seeming mental confusion, the person will exclaim or assert, BUT "this ONLY applies to isolated systems" or "this ONLY applies to closed systems". This ignorance results from people who don't read Clausius, but yet who tend to speak officially for him, in regards to the operation of the universe. The only person, to note, who has remotely carried the "magnitude of entropy is the measure of order of a thing" ideology forward into a semi-cogent readable manner or discourse has been Norman Dolloff (1975); Dolloff, however, is apex mindset wherein it becomes apparent that "Gibbs energy of formation measure of the state of existence of a thing" is the newer correct way to go about explaining order and disorder in the context of evolving or heat-driven morphing systems governed by energy and entropy.

Beyond this basic issue, earth-surface systems, e.g. a society or ecosystem, are semi-open systems, such as shown adjacent, a blend of the open + closed, such as experimented with in the van't Hoff equilibrium box models of Jacobus van't Hoff, wherein some boundaries are closed, e.g. like the walls of jail cell, whereas others are semi-open, like the guard-controlled door to a multi-person prison cell, wherein new inmates may enter or old inmates leave; or on a larger scale, the territories of gangs, or social troops (see: chimpanzee war), or the borders of countries, to name a few examples.

Quotes
The following are related quotes:

“The definition of entropy only applies when every body of the system is in a state of equilibrium. Thus, for example, we cannot speak of the entropy of the solar system.”
— John Parker (1894), Thermo-dynamics Treated with Elementary Mathematics [1]

“The second law of thermodynamics is a rather special case in that it applies only to closed systems. It does not define the steady state as this is exhibited in vital processes. Entropy may decrease in open systems. Therefore, such systems may spontaneously develop toward states of greater heterogeneity.”
— Judson Herrick (1956), The Evolution of Human Nature (pg. 51)

“The other possible escape from the evolutionist's dilemma is to say that the second law only applies to so-called ‘isolated systems’. There may well be an increase of order in an ‘open system.’ Thus, a baby grows into an adult, two animals may multiply into a population of thousands, man’s store of acquired knowledge accumulates to tremendous proportions. Even in the inorganic realm, simple elements may combine naturally to form complex compounds, and molecules may grow into crystals of beautiful complexity. All of these are open systems and their increased organization is derived from a source outside themselves.”
— Henry Morris (1976), The Bible Has the Answer (Ѻ)

“The main point is that the law of increasing entropy only applies to systems that are isolated from the rest of the universe, so that neither matter nor energy can enter or leave. In these cases, and these cases alone, the law of increasing entropy holds. The surface of the earth, however, is not a closed system. Energy enters the biosphere all the time, primarily in the form of light from the sun. It leaves primarily in the form of heat, which is radiated into space. It is this constant flow of energy that makes life possible.”
— Lee Smolin (1997), The Life of the Cosmos [2]

“It must be strongly emphasized that the principle of increasing entropy only applies to the ‘total entropy’, i.e. the entropy of the system AND the surroundings. The entropy of the system itself may increase or decrease depending on the depending on the circumstances. For an ‘isolated system’, i.e. a system that cannot exchange energy or particles with the surroundings, the principle of increasing entropy applies to the system itself (the entropy of the surroundings will not change due to the process in this case).”
— Roland Kjellander (2002), Thermodynamics Kept Simple [3]

“Strictly speaking, the principle of increasing entropy only applies to systems of conserved total energy. The universe itself is such a system, so the universe appears to be headed for a state of thermal equilibrium, after which nothing else will happen.”
— Steven Frautschi, et al (2008), The Mechanical Universe (Ѻ)

“Whether entropy's indefinable quality—its inherently ambiguous nature—is the source of its greatest strength or greatest weakness or both, it probably explains why the concept has proven to be such a seductive and persistent metaphor (I say metaphor because entropy only applies to closed or isolated systems).”
— Randall Schweller (2014), Maxwell’s Demon and the Golden Apple [4]

“The use of entropy as a metaphor has much to offer, but it is not without problems. Entropy only applies to isolated (or closed) systems, and there are no observable isolated systems. The earth itself is part of the solar system, which receives energy from—and radiates it back out to the rest of—the universe. Only the universe as a whole quantifies as a truly closed system.”
— Randall Schweller (2014), Maxwell’s Demon and the Golden Apple (pg. 35)

References
1. Parker, John. (1894). Thermo-Dynamics Treated with Elementary Mathematics: Containing Applications to Animal and Vegetable Life, Tidal Friction and Electricity (pg. 116). S. Low, Marston.
2. Smolin, Lee. (1997). The Life of the Cosmos (pg. 152). Oxford University Press.
3. Kjellander, Roland. (2002). Thermodynamics Kept Simple – A Molecular Approach: What is the Driving Force in the World of Molecules? (pg. 73). CRC Press, 2015.
4. Schweller, Randall L. (2014). Maxwell’s Demon and the Golden Apple: Global Discord in the New Millennium (thermodynamics, 17+ pgs; entropy, 78+pgs.). JHU Press.