During teacher training, there is often a review of declarative knowledge and procedural knowledge.

Declarative knowledge (factual knowledge about something). For example, history classes teach historical facts about kings and wars.

Procedural knowledge (the procedure for doing something). For example, driving classes teach (and practice) how to drive a car.

Richard ;

Thank you very much! I understand much better now. It’s somehow a postulate.

Thank you, Sir!

No, declarative knowledge is not deduction.

It is also a term that is not used very often in English.

I would guess that 98% of English speakers do not know what the term means.

Declarative knowledge involves knowing that:

Declarative knowledge means having awareness and understanding of factual information about the world —knowing/knowledge that is different than knowing how to do something (procedural knowledge).

The conditions that apply to declarative knowledge are that the information must be true, that the person must believe it to be true, and that the person must be in a position to know it. 

For example, a person can declare/state/say that:

- J is the tenth letter of the alphabet,

- Paris is the capital of France

- Princess Diana died in 1997

- the earth has one moon

- the Mandarin language is spoken by the greatest number of people. 

Hope this helps...