Computer technology has only recently become advanced enough to solve the problems it creates with its own interface. One solution, virtual reality (VR), immediately raises fundamental issues in both semantics and epistcmology. Broadly, virtual reality is that aspect of reality which people construct from information, a reality which is potentially orthogonal to the reality of mass. Within computer science, VR refers to interaction with computer-generated spatial environments, environments constructed to include and immerse those who enter them. VR affords non-symbolic experience within a symbolic environment Since people evolve in a spatial environment, our knowledge skills are anchored to interactions within spatial environments. VR design techniques, such as scientific visualization, map digital information onto spatial concepts. When our senses are immersed in stimuli from the virtual world, our minds construct a closure to create the experience of inclusion. Participant inclusion is the defining characteristic of VR. (Participation within information is often called immersion.) Inclusion is measured by the degree of presence a participant experiences in a virtual environment. We currently use computers as symbol processors, interacting with them through a layer of symbolic mediation. The computer user, just like the reader of books, must provide cognitive effort to convert the screen’s representations into the user’s meanings. VR systems, in contrast, provide interface tools which support natural behavior as input and direct perceptual recognition of output. The idea is to access digital data in the form most easy for our comprehension; this generally implies using representations that look and feel like the thing they represent. A physical pendulum, for example, might be represented by an accurate three-dimensional digital model of a pendulum which supports direct spatial interaction and dynamically behaves as would an actual pendulum. Immersive environments redefine the relationship between experience and representation, in effect eliminating the syntax-semantics barrier. Reading, writing, and arithmetic are cast out of the computer interface, replaced by direct, non-symbolic environmental experience. Before we can explore the deeper issues of experience in virtual environments, we must develop an infrastructure of hardware and software to support “tricking the senses” into believing that representation is reality. The VEOS project was designed to provide a rapid prototyping infrastructure for exploring virtual environments.