Chronotype and beyond: 17 building blocks to reconcile and explore internal time architecture.

Chronotype, defined as the temporal phenotype of an organism, has been addressed in Chronobiology International in some 200 publications between 1997 and 2018. Readers may thus be interested in what roles chronotype may play in studies concerning chronobiology and health. In line with Karl Popper, our objective is to synthesize terms and concepts for falsifiable experimental, field, and ultimately epidemiological research. To this end, we offer 17 building blocks where each should follow from one or more others. Such "causal" tabulation may be requisite for understanding chronotype and multi-faceted internal time architecture beyond intuition and common sense. Overall, our "causal" box tabulation allows to challenge, explore, falsify, modify, or corroborate complex facets regarding internal time, step-by-step. Clearly, if our espousal of building blocks were to lead to refined replacement blocks, thereby forcing researchers to produce more and more convincing evidence and chronobiological insights, individuals and populations would benefit.