At first glance, understanding the action should not cause any difficulties. Well, what could be wrong with it – everything is as simple as possible. Everyone can see how objects move and interact, everyone can move their hand. Everyone took a school physics course. But this simplicity contains many features that we simply don’t think about – they live in our heads as a matter of course. Let us reveal these properties explicitly, since the construction of logic depends on them.

Action refers to the application of some force. It is not necessary that force can only have a physical nature – it can be chemical, electrical, electronic, biological and other nature of force. The application of force is a manifestation of energy. Push or constant rotation is the generation of kinetic energy. An engine converts matter into energy or one type of energy into another type of energy. An electric motor converts electrical energy into kinetic energy.

Action requires energy, since action involves the output of energy, which means that at its input there must also be energy or some substance that can be converted into energy (for example, fuel and oxidizer). In physics, there is an empirical law of conservation of energy, which is detailed for each type of energy. The incoming energy or substance is the resource that provides the action.

In a car (as an example) there are two concepts standing next to each other: engine and propulsor. The engine produces energy from fuel and oxygen (ICE – internal combustion engine) or from electricity (electric motor). An engine converts matter into energy or one type of energy into another type of energy. The propulsor of a car is the tires. They come into contact with the external environment, with the road, and transfer energy to the road in the form of force (acceleration or braking). Due to this, the car moves, it is the subject of the action, that is, the object on which the action is applied. The propulsor (the mover) is tied to the subject of the action.

The object of an action is the object that performs the action. Since the object performs an action, the engine is tied precisely to the object of the action.

Action is a process; it exists in some object. For action, this is the external environment.

A few examples:

• Hang glider. It does not have its own engine, but it flies, “riding” the air: wind and air flows. Action is flight. The external environment is air. Engine – wind, air currents. The propulsion unit is the wing. The flight is controlled by the hang glider itself (more precisely, by the person who controls the hang glider) through the wing as a propulsion device.
• A stone that flew when kicked. The external environment is air (a stone flies through the air). The subject of the action is the stone. The object of action, the engine, is the leg. The mover is the surface of the stone itself. Flight is controlled by the object that applies the force. The stone itself does not regulate the action.
• Airplane. The object of action and the subject of action is the plane itself. The engine is actually the engine of the aircraft, the propeller is the wing. The airplane is controlled both by the application of force itself – the engine power, and by the propulsion force – the wing.