A modern observer is one that is in control of what it sees, and is the entity in charge of interpreting the outside world. A modern observer is not a passive spectator - it is an interpretor and thus creator of the outside world. Each individual modern observer has its own version of a spectacle as a result of "'what occurs within the brain'" (Crary, 75). In Schopenhauer's opinion, the concept of beauty depends on each individual brain (Crary, 84). 

As part of a human/animal, the eye is subject to bodily functions including fatigue (Crary, 73). The human body as a machine of sorts, as a functioning body that needs fuel or energy to run, is in this was seen as prone to error in interpretation of the spectacle. The excess or lack of nutrients in the bloodstream could warp the colors seen by the eye, transform scents, or heighten sharp tones in music. The modern observer recognizes its ability to misinterpret stimuli due to biological variations - this is what makes an observer powerful. 

Johannes Muller's work with senses brought in a scientific take that supported the independent nature of sense perception (Crary, 89). The separate nature of each sense's reception lends itself to a variety of interpretations derived from pairing two (or more) different sensory signals. The way each brain determines the product of multiple sensory inputs is more varied and the modern observer thus hold more power over both the spectacle and its own perception. Since the sensory inputs, comprised of electrical or chemical stimuli, are merely biological and are separated, the brain, a final station for deriving meaning and synthesizing information, is king.