 Hempel remarks that his model of explanation does not directly apply to the wordless gesticulations of a Yugoslavian automobile mechanic or guarantee that explanations that are adequate are invariably subjectively satisfying. His purpose was to formalize the conditions that must be satisfied when an explanation is adequate without denying that background knowledge and prior beliefs frequently make a difference in ordinary conversational contexts. Jan might not know some of the antecedent conditions, Jim might have misunderstood the general laws, or features of the explanandum event may have been missed by them both. Even when information is conveyed using diagrams and simulations, for example, as long as it satisfies conditions  (CA-1)  through  (CA-4)—no  matter whether those conditions are satisfied implicitly or explicitly—an adequate scientific explanation is at hand. But it has to satisfy all four of those requirements.