At the crossroads of geomorphology’s ‘quantitative revolution’ one can identify three main approaches towards understanding the form and mechanics of landscapes: probabilistic descriptions of particle motions, the mechanics and rheology of granular materials, and field measurements and observations. These approaches are typified by the pioneers Einstein, Bagnold and Leopold, respectively. Although these workers may sometimes overlap in method they are ontologically and epistemologically distinct, which leaves a lasting impression on contemporary geomorphic practices. Inspired by AGU’s centennial, this panel-format session and accompanying poster session seeks to: present evidence marking ontological branching in our discipline, showcase contemporary practitioners and progress within each stream, and explore if the genealogical network of workers appropriately fills the space of possible geomorphic discovery.