Studying laws under which heat and energy is transferred in any system – a problem of science of thermodynamics. Whether but everything its laws are absolutely clear to you? Let's understand together.
Law of energy conservation
In fact, the first law of thermodynamics is a special case of the law of energy conservation. This law is familiar and clear practically to everyone: energy does not appear and does not disappear, and only passes from one look into another. It is interesting that the first law of thermodynamics, though is final and absolutely proved, has several various formulations. But, believe, there is no contradiction here. Just each of them explains a law essence a little in own way. Let's sort them everything as it will help to understand contents of the law better.
Formulation 1
In the isolated thermodynamic system the sum of all types of energy is a constant.
Here everything is, seemingly, clear. By analogy with the law of energy conservation, it is possible to explain the first beginning of thermodynamics very simply: if the system is closed, no energy leaves it and does not come, and their total amount does not change what processes would not happen inside. Also there is a similar formulation saying that emergence or destruction of energy is impossible.
Formulation 2
Any form of motion is capable and has to turn into any other form of motion. Agree, it is a little philosophically. However it also captures the essence of the first law of thermodynamics. If energy does not disappear anywhere and cannot appear from anywhere, in a system there is a continuous transformation of one energy into another. Though in this treatment it is about form of motion, the essence does not change. The movement of a body, a molecule or stream of particles can be considered as subjects of the law too. By the way, the first law of thermodynamics claims also that existence of the perpetual motion machine of the first sort (that is, existing without foreign intervention) is impossible in principle. Sometimes it is also considered the independent wording of the law. The same reason – energy does not arise in itself.
Let's sum up the result
So, generalizing everything told above, it is possible to remove simple interpretation of the first law of thermodynamics. Any system is not capable to exist (that is, to perform any work), without message to it a certain amount of energy. By the way, the first thermodynamic law is well-known also that it is very often treated by philosophers and theosophists, applying to concepts, from physics very far. Well, any theory has the right for existence. Especially as the person – just the same system, as well as any other.