Stop trying to carve Nature at its joints! The importance of a process-based developmental science for understanding neurodiversity.

Nature is dynamic and interdependent. Yet we typically study and understand it as a hierarchy of independent static things (objects, factors, capacities, traits, attributes) with well-defined boundaries. Hence, since Plato, the dominant research practice has been to 'carve Nature at its joints' (Phaedrus 265e), rooted in the view that the world comes to us pre-divided - into static forms or essences - and that the goal of science is to simply discover (identify and classify) them. This things-based approach dominates developmental science, and especially the study of neurodevelopmental conditions. The goal of this paper is to amplify the marginalised process-based approach: that Nature has no joints. It is a hierarchy of interacting processes from which emerging functions (with fuzzy boundaries) softly assemble, become actively maintained, and dissipate over various timescales. We further argue (with a specific focus on children with Down syndrome) that the prevailing focus on identifying, isolating, and analysing things rather than understanding dynamic interdependent processes is obstructing progress in developmental science and particularly our understanding of neurodiversity. We explain how re-examining the very foundation of traditional Western thought is necessary to progress our research on neurodiversity, and we provide specific recommendations on how to steer developmental science towards the process-based approach.