Holes ​

The concept of "hole" in language is defined as something nonexistent, a "hollow". In a soap bubble, a hole is the place where there is no soap. But in the engineering world, a hole/opening/cavity exists as a separate concrete object in the physical world: it can be created (drilled), it can be covered with some coating. A well is a hole in the ground, oil workers often call it a "hole" in slang: it is valuable precisely because there is nothing in the well, so oil or gas can be pumped through it. A "pass-through" (for example, a cable pass-through) is a device with an opening through which another engineering object can be passed through (in a cable pass-through - a cable, in a roof pass-through it could be a cable, pipe, antenna, etc.).

If we remember that a hole occupies a certain volume, a certain place in space-time, then we can give it a name (engineers do just that) and discuss some technological operations with it - manufacture, accounting, inspection, repair, "tuning". Moreover, this is a good criterion for determining whether such a "hole" should be named: if there is some operation (work done according to a certain method, leading to a change of state) with such a "hole", then it would be better for the "hole" to have a separate name for accounting and checking its state after such an operation.

A hole/cavity occupies a place in space-time, therefore, it is present in the physical world. A "working cavity" in a compressor is also a "hole", a working space in a pipeline is also a "hole". It is easy to think of them by imagining this space filled with gas or liquid molecules, or even a vacuum - the physical substance is not important here. What is important is how to think about it, and one should think about the places in the physical world, areas/volumes of space/time.

An intermission is a part (in time) of a concert or performance when there is no show. Reasoning about an intermission can be done in the same way as about engineering openings, but it will not be a spatial part, but a part in time/temporal part of a performance or concert as a material object, a realization of a system. The "culmination of the performance" can also be represented as a completely material part: it is the temporal (in time) part of the performance where maximum emotional intensity is reached. On the other hand, it can be considered that this part takes a negligible amount of time, and then the "culmination of the performance" will be an event - and the temporal parts will be important before and after this event.

How to think about an intermission or culmination as temporal parts of a performance? These will be all the objects of the performance (all the molecules of the objects involved in the performance - actors, props, audience) in some period of time.

One can also deal with strange objects that need to be accounted for by name (because some actions need to be carried out with them), but which are difficult to distinguish as separate from the physical object - for example, welded seams. A welded seam needs to be designed, then made, and then regularly checked. This means that the instance of a welded seam should have an individual name, it is a specific physical object that occupies a place in the physical world. If one understands that a welded seam is simply a place in space (and time!), then there are no problems in thinking about such an object: it is as much a part of the system as the pipe itself, or a gear, or an opening. They can have their parts (although in the seam there are molecules, and in the opening there are no molecules, but there is a space that molecules could occupy!), they enter as parts into other material objects, they can have descriptions.

This somewhat contradicts the concept of a "configuration of matter resistant to the destructive action of time" as a system in physics. Thus, if one looks at the flame of a candle, researcher Karl Friston notes the impossibility of indicating the boundary of the system, as there is some disorderly exchange of molecules with the surroundings. But if an engineer takes over, for him the "flame" is a perfectly valid object, the state of which can be measured (for example, measuring the temperature in the center of the flame and at its imaginary boundary). And the engineer will define this flame by its spatial form in the surroundings and the need to perform certain operations with this form: the engineer will have the same reasoning here as with the "opening". And the flame will be perfectly stable for him, and the welded seam with its blurry boundary between the seam itself and the material at the molecular level - will also be stable.

One can further explore such changes of states and objects that change state in the course of an instantaneous/simple event or a complex event taking some time - depending on the consideration. For example, in 3D printing of rocket bodies, one can easily imagine a rocket body consisting of a continuous "welded seam" - in fact, it is about continuous metal deposition. It is important to understand that the temporal scale of observation/scale of the temporal part of the system also matters. In a large time scale, "there was no body here - here it is", and in a small time scale, "we added one coil of metal deposition to the body, and this happened thousands and thousands of times". And what matters are not so much some "objects" perceived as "usual solid objects", as the space-time occupied within the boundaries of the system. In time, these boundaries of the system (or states of the system) are events, in space - form/place. Events and forms/places - these are boundaries of the system or states of the system.