I am fascinated by the way that concepts about the reality of the universe are developed. The fact that we can quantify what we perceive enough to discover what we do not perceive. It is used in the way that artists use positive and negative space. We can determine an object by the space around it.
It is this careful construction of idea, the tentative process of pulling together other ideas and blending them in ways that would be considered unconventional that really draws me to the particle physics. Theoretical physics can see the gaps in the maths to begin to reveal what was previously not perceivable.
This is an exciting starting point.