Older documents on function analysis define the following: “A function is an action performed by a component to change or maintain a parameter of another component. Preserved here means that the parameter would not exist without the action.”
A much better and more correct formulation would be: “A function is an action performed by a component to change the value of a property of another component or to keep it stable. “Keep stable” here means that the value of the property is fixed by the function and is prevented from changing.”
We already discussed this in the last post, but let’s take a closer look at “keeping stable”. How can we be sure we have the correct wording here?
For example, the function of a microwave is “heats food”. The property energy content, represented by the property “temperature” of the object “food” increases its value. The function of a curtain rail would be “holds curtain”. The “Position” property of the “Curtain” (the specific location would be the value for this) is prevented from changing its value.
Keep functions (or “keep stable” functions) can be easily identified using the magic wand method: I imagine I have a magic wand with which I can simply make components disappear.
So if I have dust on a window and I’m not sure whether the function should be called “Dust stains window” or “Window holds dust”, then I imagine that I can use my magic wand to make the function carrier disappear. Then I ask myself whether anything happens to the object of the function. If yes, then I have a legitimate function. If not, then it is not a correctly formulated function. In our example, the window would not change if I simply conjured the dust away. The window is still the same under the dust. If, on the other hand, I mentally remove the window with “Window holds dust”, then the dust would float to the ground. So the window determines the position of the dust.
What do you think of my magic wand method? How do you check the correctness of the formulation of a function?
(Image created with Midjourney.)