Facts can be understood only when they relate to an idea.
To use a simple example, we can recognise all types of furniture as chairs because we have an idea of what a chair is. This is how we know a folding chair and a lounge chair are both chairs. Without this idea, we wouldn’t be able to distinguish what a chair is, and the world would be even more confusing.
Ideas come before our understanding of facts, although the abundance of facts can obscure this. A fact can only be understood within the context of an idea. And ideas are subjective, which makes facts subjective too.