I've noticed a terrific number of authors talk about "entropy transfer" across a system boundary. But entropy is defined as log(multiplicity), and is a measure of available states to a system in a given configuration. We can transfer mass, charge, energy, from one system to another, and thus destroy A available states in one system and produce B available states in the other. But the available states depend on the composition and configuration of the system, and vary from one to another. When I transfer a particle among states, I know that the particle I started out with in one system is the particle I ended up with in the other. But if I were to talk of transferring "available states" among systems, that would not be the case - not only would the numbers be different, the states themselves would be different. Introducing a Cu ion to an insulating crystal is very different from introducing it to a conducting copper wire - not only will the number of new available states be in general different from each other, the states themselves will very different from each other. In the insulating crystal the valence band is completely filled and the ionic charge will go into the conduction band which sits a band gap above the valence band. In the conducting copper wire, the valance band is no completely filled, and that's where the ionic charge will go (I know, it's not *this* simple, but you get the point - different states, not just different numbers of states). So how in the world can we possibly be talking about transferring entropy across systems, when there is no correlation between what one system gives up and the other receives? I cam take one particle from system A and give it to an infinite number of different systems, and the new states created will in general be all different from each other - and hence the entropy changes will so differ. Imagine I have an apple in my hand and I "give it" to you - but the moment you receive it you find you now have a corn stalk in your hand instead. I can't be entitled to say I transferred anything to you because I can't say what I transferred. I didn't transfer an apple because you never received one, and I never transferred a corn stalk because I never had one to transfer. If my apple exists as such only so long as it's in my hand, I can't possibly talk of transferring apples to anybody, because "apple" is a function of belonging to me - the moment I try to give it to somebody else, "apple" is no longer, and something else appears. So, I find it absolutely and completely and utterly senseless to talk about transferring entropy. What we *can* transfer is mass, charge, energy, etc - we can then analyze the effect of changing these quantities on the multiplicity of the system. But we cannot be able to transfer states. Opinions?