This paper examines the rationalist conception of evidence as advocated by Jordi Ferrer and its proposal to formulate precise and objective standards of proof. First, three concerns are raised about the characterization of the rationalist conception as discussed in: i) its historical background, ii) its defining features, and iii) the contrast between a rationalist conception that focuses exclusively on evidence and a persuasive conception that focuses on the beliefs of the trier of facts. Second, it is argued that the search for an objective and precise standard of proof should be abandoned, both because it is futile and because it contradicts the probabilistic nature of evidential reasoning. Finally, it is suggested that an adequate theory of the sufficiency of evidence should be able to accommodate and explain (a) the current formulation of standards of proof notwithstanding the problems of subjectivity and imprecision, (b) a rigorous analysis of evidence that includes both an individual and an overall evaluation of evidence, and (c) the beliefs of the trier of facts. I argue that a theory of evidence should integrate evidence and persuasion as two basic components of evidential reasoning.