Empiricism holds that scientific knowledge is based on data or evidence; justificationism claims that all knowledge consists of justified true beliefs. Together, these ideas lead to anthropocentric and reductionist portrayals of science that say we use sense data to justify our beliefs about the world. But scientific knowledge does not consist of evidence-based true beliefs. It consists instead of conjectural explanations, created by people attempting to understand the world. Scientific knowledge therefore explains our sense data, but our sense data never justifies our scientific knowledge: regardless of whether, or with how much certitude, those explanations are “believed”.