Data comes in through our senses from the external reality. This is the raw material for input from nature. Knowledge begins here.
The most prevalent form of knowledge comes from our observations. We perceive with our eyes. The knowledge from the senses is the start of knowledge.
From the grounded measurements of observation, we can use our intellect and imagination to abstract and form relationships. Abstractions are formed from recognizing the commonality of similar objects. Logic and induction is the method to brings data together and try to form general or universal conclusions about it.
The abstracted qualities found in similar aspects of reality can be refereed to as an essence they share. The abstractions can be integrated to form conceptions. The essence is the universal or general concept that links the particular specific perceptions.
Universal concepts comes from reality as an objective norm. In order to define and communicate about it, we form subjective arbitrary symbols in our minds. This allows us to share knowledge and arrive speak about various truths that are found in the reality we all share in common.
From reality we abstract images, idea and concepts that share qualities, properties, and characteristics. There are classifications that can be made to sort things and create symbols or words to represent those classifications. The images we have in our minds can then be expressed.