Macro-historical studies often "assume that macro-historical processes repeat themselves in explainable and understandable ways". In retrospect, such events are explainable, even overdetermined. Besides Divine Providence, Villani acknowledged other events that he believed were explainable via the supernatural. Atomic radii vary in a predictable and explainable manner across the periodic table. More fundamentally, many algorithms used in machine learning are not easily explainable. The morphological variation is explainable as a factor of elevation. The ability to explain cause and effect is an important aspect of explainable AI. In other words, de Vries's experiments were explainable by the Mendelian-chromosome theory. Furthermore, for some explainable reason, he may be unable to comply, despite diligence. This is not explainable by neutron reflection alone. This alarms Luce, but she dismisses it as something explainable. This oil comes to the carved shape with no explainable source or reason. In contrast, trends have explainable rises, and are driven by functional needs. Oettinger spoke of a "horrible and in no way explainable crime". So it was explainable that his voice sounded so gentle while singing.