Agent English meets with Ophelia at the bar and has a short conversation with her. After she leaves, he tells his assistant, Bough, how charming she is and how she's totally innocent. Bough presents suspicious information about her, but English dismisses each piece of evidence by making up some excuse.
Beakman explains how the brain uses perception to gather visual and auditory cues and puts together what likely happened. This is used in filmmaking to make things look like they are really happening. Beakman explains how stunts are done by tricking the viewer's perception of what happened.
Liza explains that our brain processes information from our senses and makes conclusions (perceptions) about our environment. When these perceptions are wrong, this is an illusion. They show a few examples of an optical illusion.
Jerry Andress explains several optical illusions and suggests that the discrepancy between our perception and the reality is not a mistake of the brain; the brain tried its best to map out the reality with whatever information it had.