section_path: Central concepts/Other concepts
section_name: Other concepts
paragraph_text: Other concepts
  
  Rationality is closely related to justification and the terms rational belief and justified belief are sometimes used as synonyms. However, rationality has a wider scope that encompasses both a theoretical side, covering beliefs, and a practical side, covering decisions, intentions, and actions. There are different conceptions about what it means for something to be rational. According to one view, a mental state is rational if it is based on or responsive to good reasons. Another view emphasizes the role of coherence, stating that rationality requires that the different mental states of a person are consistent and support each other. A slightly different approach holds that rationality is about achieving certain goals. Two goals of theoretical rationality are accuracy and comprehensiveness, meaning that a person has as few false beliefs and as many true beliefs as possible.
  
  Epistemic norms are criteria to assess the cognitive quality of beliefs, like their justification and rationality. Epistemologists distinguish between deontic norms, which are prescriptions about what people should believe or which beliefs are correct, and axiological norms, which identify the goals and values of beliefs. Epistemic norms are closely related to intellectual or epistemic virtues, which are character traits like open-mindedness and conscientiousness. Epistemic virtues help individuals form true beliefs and acquire knowledge. They contrast with epistemic vices and act as foundational concepts of virtue epistemology.
  
  Evidence for a belief is information that favors or supports it. Epistemologists understand evidence primarily in terms of mental states, for example, as sensory impressions or as other propositions that a person knows. But in a wider sense, it can also include physical objects, like bloodstains examined by forensic analysts or financial records studied by investigative journalists. Evidence is often understood in terms of probability: evidence for a belief makes it more likely that the belief is true. A defeater is evidence against a belief or evidence that undermines another piece of evidence. For instance, witness testimony connecting a suspect to a crime is evidence for their guilt while an alibi is a defeater. Evidentialists analyze justification in terms of evidence by saying that to be justified, a belief needs to rest on adequate evidence.
  
  The presence of evidence usually affects doubt and certainty, which are subjective attitudes toward propositions that differ regarding their level of confidence. Doubt involves questioning the validity or truth of a proposition. Certainty, by contrast, is a strong affirmative conviction, meaning that the person is free of doubt that the proposition is true. In epistemology, doubt and certainty play central roles in attempts to find a secure foundation of all knowledge and in skeptical projects aiming to establish that no belief is immune to doubt.
  
  While propositional knowledge is the main topic in epistemology, some theorists focus on understanding rather than knowledge. Understanding is a more holistic notion that involves a wider grasp of a subject. To understand something, a person requires awareness of how different things are connected and why they are the way they are. For example, knowledge of isolated facts memorized from a textbook does not amount to understanding. According to one view, understanding is a special epistemic good that, unlike knowledge, is always intrinsically valuable. Wisdom is similar in this regard and is sometimes considered the highest epistemic good. It encompasses a reflective understanding with practical applications. It helps people grasp and evaluate complex situations and lead a good life.