GLOSSARY

Cre-actor: A cre-actor (for creator-actor) is the user of a virtual reality system, who builds and tests a virtual universe he/she is taking part in, in virtuo. While participating as an actor in the artificial life within virtual universes, this user can also shape the universe in question at his/her own will.

In virtuo experiments: An in virtuo experiment is one carried out in a virtual world of interacting digital models in which a human being is taking part. Like a biologist performing in vitro experiments, an in virtuo experimenter can observe phenomena as if he had a virtual microscope which can be moved and oriented as wished, with a choice of focal points. The cre-actor user (spectator-actor-creator) can thus focus on observing a specific type of behavior, or observe a subsystem's activity or the overall activity of the system. The user can interrupt the phenomenon at any time, accurately focus on the bodies present and the interactions underway, and then restart the simulation where he/she had stopped it. At any time, using sensory-motor behavioral interfaces, the user can disturb the system by modifying the property (status, behavior) of an element or by removing elements or adding new ones; meaning he/she can test a specific behavior, or more generally speaking, an idea, and immediately observe the consequences on the system under operation.

In virtuo: In virtuo (in the virtual) is a newly coined expression constructed like adverbial phrases from Latin such as in vivo (in the living) and in vitro (in glass). The expression in silico (in silicon) is often seen when speaking of computer calculations, however, in silico fails to conjure up human participation in the world of digital models as they are running, which is why we prefer in virtuo, whose common root provides a reminder of the experimental conditions of virtual reality.

Model: A scientific model is a representation which can be physical, graphic, or more generally, mathematical. It formalizes the relationships which link the various elements of a system, a process or a structure, with a view to facilitating understanding of certain mecanisms or enabling a hypothesis to be validated.

Modeling: Modeling is the action of intentionally, through the composition of symbols, designing and building models which could render a seemingly complex phenomenon intelligible. It also amplifies the reasoning of the actor who plans to deliberately intervene within the phenomenon, this reasoning particularly aiming to anticipate the consequences of plans for possible actions.

Virtual reality: Virtual reality is a scientific and technical field using information technology and behavioral interfaces to simulate the behavior of 3D entities in a virtual world. They interact with each other and with one or more users in real time, through pseudo-natural immersion via sensory motor channels.

Simulation: Scientific simulation means experimenting on a model. Traditionally, it is considered that there are four main kinds of models, ie perception, formal, analog and digital models. Their experimentation has currently led to five main families of simutation: in petto intuition resulting from perception models, in abstracto reasoning within formal models, in vitro experiments on analog models, in silico computations on digital models, now extended by in virtuo experiments on these digital models.

Complex system: A system's complexity essentially comes from the diversity of its components, the diversity of its structures and the diversity of the interactions put into play. Therefore, a complex system is on the face of it, an environment which is open (components appear/disappear dynamically), heterogeneous (varied behaviors and morphologies) and made up of mobile composite entities distributed over space and in varying numbers over time. These components, amongst which humans and their free will often play a determining role, can be structured into different levels, either known from the start or emerging as they evolve due to multiple interactions between the components. The interactions themselves may be of different types and operate on different spatial and time scales.

Virtuoscope: The virtuoscope is a virtual laboratory for the study of complex systems, based on virtual reality concepts, models and tools. Virtual reality puts the user at the heart of the virtual laboratory, bringing him/her closer to the methods of experimental science while providing access to digital methods.