Feldman’s full Brian/Brain objection:

Brian is a normal person with accurate and well justified beliefs about the world around him. Brain, a Brain in a Vat, is Brian’s mental duplicate, and has experiences just like him. Brain also has beliefs that are analogues, or the same, as Brian’s. When Brian believes that he, Brian, is eating a hot fudge sundae, Brain believes that he, Brain, is eating a hot fudge sundae. When Brian believes that he, Brian, is taking a walk in the park, Brain also believes that he, Brain, is taking a walk in the park. This also applies to seeing objects, as when Brian believes that he, Brian, is seeing a bright red object: Brain also believes that he, Brain is seeing a bright red object. While Brian is right about each of these things, as he usually is, Brain is wrong every time. According to the process reliabilist, Brian knows these things and therefore his beliefs are justified, which he does. Brian’s belief forming processes are extremely reliable as a result. However, Feldman argues that a major problem arises with Brain: Feldman argues that Brain also has justified beliefs just like Brian, however, Brain’s justified beliefs have routinely led Brain to false conclusions. Therefore, Feldman concludes that justification is not necessary for forming true beliefs. Feldman’s Brian/Brain example looks extremely bad for the process reliabilist, as the Brian-Brain example provides a situation where an individual has a reliable, justified, belief-forming process, yet routinely arises to a false conclusion.