... nature has very few good ideas — it recycles them in subtle and interesting ways, over and over again — and it's our job to understand how that w… - Nima Arkani-Hamed

Two of the major questions left unanswered by the Standard Model of particle physics have to do with hierarchies of mass scales. The first is the flavor problem: what determines the masses of the quarks and leptons, and why do they span such a large range, e.g. why is the top quark 3 × 10⁵ times heavier than the electron? The second is the gauge hierarchy problem: why is the weak scale seventeen orders of magnitude smaller than the Planck scale?

The stakes are higher than the past. We aren’t asking about this or that particle, but something much more deeply structural about physical reality. … By far the best way to settle this question is to lead a charge to the highest possible energies and build a 100-TeV collider.

The hierarchy problem is the elephant in the room. ... And it originally showed up in the context of doublet–triplet splitting problem.