Asking "why?" gets to the heart of any concept
Conceptual space is like a landscape. Iteratively asking "why?" helps to explore this hidden landscape and leads to malleable truths which can be applied to other concepts.
This can also be used to create an outline for an essay. Take your main point and iteratively ask why until you get to the core of the idea, then flip this sequence so that your essay starts with your last answer and builds up towards your main argument.
But beware: This will only get to the heart of what you know and understand from your own perspective, someone else may come across a very different sequence of answers.