This category includes concepts which are classes of real objects or situations, etc. A child can learn this concept by direct experience of a variety of red objects and other objects which are not red. This category includes concepts which are classes of other concepts. These cannot be learned without the use of a suitable language. The examples that make up the class described by these words are themselves concepts.
Every real object has a colour and a size.
This category includes sets of related concepts which, it is hypothesized, the learner stores in his memory in such a way that the relation between concepts. as well as the concepts themselves, are remembered and can be recalled. Thus such physical properties as mass, weight, density or size may be stored in such a way that the interrelationships between them are also remembered, or alternatively they may be stored as separate concepts. In the latter case, it is less likely that such secondary conclusions would be made correctly. This category includes all principles or laws that we can see to be in operation in the world around us, either by direct observation or by inference from the effects. A rule is a statement of a relationship that exists between two or more concepts or phenomena.