Photography as exploration vs. Photography as Illustration
The first approach makes no assumption about what is there, it is open and waits for the subject to speak for itself.
The second attempts to visualize an idea: It is looking into the subject to find an expression for what has already been defined. It uses the subject as a vessel for an emotion or an idea.
Neither of these approaches is pure: The subject will never only speak for itself, as you can only listen to the things you are made to hear.
And no matter how much effort you put into moulding the world into a shape, there will be remains. A substance you did not put there. The subject will always resist your effort to use it as a vehicle for your ideas. It will taint your thoughts and speak with its own voice, even if you make it speak your words.