For the definition of includes, see part 1.

Includes

Include 'referring'

Part 2: A closer look at Objects

The question is if glue and paint are also such objects or not?

It contributes to the properties of the compound object, the color it has, or the separate parts of it. It is also something that can be touched, because if you have paint or glue on your fingers you can feel that. So paint is also an object. An object where on the properties is that it is liquid. It is liquid when wet, and hard when dry.

So this means that the properties of an object can change. Paint can be liquid, then become hard, and later on be made liquid again. But this depends on its properties. Several properties of an object can influence each other. That paint can be made liquid again, after it has become hard, depends on some of its properties. Some paints can, others can't. Yet they are all called paint. They belong to the class "paint."

What is a class? Where does it differ from a collection? What is a collection?

A class means there is a object, with which all following objects above it have the same thing in common. You will notice here that I write above, and not below. We humans look from above, and say that a class has children and we draw a structure from the top to the bottom. But nature does not work this way. It works from the bottom up. The least complex objects are at the bottom and the more complex ones near the top. It is this logic I will follow, not only in the text but also in the images.

This might make it harder for you to follow, but once you get used to that way of thinking you will understand its benefit. For example when describing the class chairs, I will still speak about the head object, even while this object is at the base. It is the one that they all have in common.

I go back to the example of paint, the basic paint, the base object with which all other objects of the class have the same things in common. In the case of paint, there are certain properties all paints have in common. They have a color, they are meant to paint, and some others. The base object of the class "paint" is not necessarily a real object, one you can hold.

Different paints that are constituted of different materials still belong to the class "paint," even if the colors differ. This is because they belong to a class of compound objects which in language we refer to as "paint." There is a difference between the classes we use to describe objects in language and the real classes to which those objects belong to.