 In the case of ordinary perceptual experience, an object instantiates an observable property, such as being red, and this causes us (in the right way) to have a corresponding phenomenal representation of the object, such as a visual experience of a red object in front of us (Audi 2013). Many believe that this experience is not itself a belief: I can believe that a stick in the water is straight while it nevertheless perceptually appears to me that it is not straight. However, ordinarily having a perceptual experience provides justification for a corresponding belief, either because it presents or represents things as being in a particular way (as epistemological internalists think) or because it reliably informs us of them being that way (as epistemological externalists think), or a combination of these. Epistemologists debate whether justification requires only the absence of defeaters or also some type of warrant to rule out skeptical scenarios, and what needs to be added for a true belief to amount to knowledge.