1. Knowledge vulgar, scientific and philosophical
Men have different knowledge, common or vulgar, obtained by sight, hearing and other senses, in a natural way, without study and without knowing about the causes. Scientific knowledge is the rational explanation of why things happen. It explain the causes of the things, and why they happen. It is known as the general law.
Philosophical knowledge is deeper than scientifical and tries to explain the final cause.
In other words: common knowledge put the focus in the why of the things, scientific knowledge answer the questions, and philosophical knowledge try to explain the final causes of human intelligence.
Example: a farmer knows by his experience that a certain field is better than other for cereals. A scientist knows the field is good for cereals because he analyses its elements in a laboratory. A philosopher asked himself why we must trust in scientific laws. Are them safe or constant?
Other example: an ill man has a headache. The doctor knows why is he ill and the cause of his pain. A philosopher asked: Why is the cause of the pain in the world?