There are some concept that most people (if not sometimes all people) fail to accurately define - eventually because the concept does not match a natural category - however we all have a good enough intuition about what is encompassed by the concept for most practical uses.
Is there a term that refer to the existence of such concepts with inexistant clear definitions but for which our common intuition is enough for practical usage?
Here are a few examples coming to mind:
- Happiness
- Complexity (outside of computer science, a dolphin feels more complex than a worm)
- Game
- Beauty
- Awareness
- Big (like in "it is a big number")
You, dear philosophers, experienced in working out the epistemology of such 'complex' concepts might have a much better notion than me of a commonly accepted definition of the above examples. Whether a definition exist for the above concepts is not so much the point of my post. My question is "Is there a term to describe such concepts?"