From Wikipedia, the free encyclopedia

The term virtual is a concept applied in many fields with somewhat differing connotations, and also, differing denotations.

Colloquially, 'virtual' has a similar meaning to ' quasi-' or 'pseudo-' (prefixes which themselves have quite different meanings), meaning something that is almost something else, particularly when used in the adverbial form e.g., "He's virtually [almost] my boyfriend". The term recently has been defined philosophically as, that which is not real, but may display the full qualities of the real.

• Virtual images — A certain type of image that does not project onto a screen, but can be perceived
• Virtual particles — Particles that exist for a period of time that is not long enough to define their energy mathematically
• Virtual work — Involving force and displacement

• Virtual artifact (VA) — a representation rather than the ‘real’ thing, an immaterial object that exists in the human mind or in a digital environment
• Virtual host — A function of modern web servers that allows more than one website to be hosted on the same server
• Virtual memory — Memory that may not exist physically, but is made to appear so, by software
• Virtual machines — Software based partitions of a single computer that function as if they were independent computers
• Virtual function — Allows a derived class to override functions in classes from which it inherits
• Virtual reality — A popular science fiction/IT concept, defining an artificial environment that is simulated by computer hardware and software
• Virtual storage — Computer storage in which virtual addresses are mapped into real addresses
• Virtual world — A computer-simulated environment
• Virtuality — The opposite of reality, as used by Ted Nelson
• Virtualization — The concept of establishing and managing virtual machines or other virtual resources that share physical computing hardware

• Virtual community — A group of people connected on-line, using the Internet
• Virtual museum — An on-line, simulated museum
• Virtual school — A school where students can do coursework on-line
• Virtual sex — Alternative term for cybersex
• Virtual shopping — A term for business-to-consumer electronic commerce (B2C)
• Virtual tourism — Use of digital resources, especially on-line, for tourism, of simulated tours

Numerous philosophers have advanced conceptions of the virtual.

The current definition, that can hardly be distinguished from potential originates in medieval Scholastics and the pseudo-Latin "virtualis".

Most prominent of these in contemporary philosophy has been Gilles Deleuze, who uses the term virtual to refer to something that every object carries with it, which is neither its reality, nor merely what it could have been, but rather what it is imagined to be. "Virtual" is therefore taken to mean a potential state that could become actual. "Virtual" is not opposed to "real" but opposed to "actual," whereas "real" is opposed to "possible."

Recently this conception of the virtual has been challenged and another core meaning has been elicited by (Denis Berthier, "Meditations on the real and the virtual" — in French). It is based both upon science (virtual image), technology (virtual world), and etymology (derivation from virtue — Latin virtus[1]).

At the same ontological level as "possible," "real," or "potential," "virtual" is defined as that which is not real, but displays the full qualities of the real — in a plainly actual (i.e., not potential) — way. The prototypical case is a reflection in a mirror: it is already there, whether I am here to see it; it is not waiting for any kind of actualization.

This definition allows one to understand that real effects may be issued from a virtual object, so that our perception of it and our whole relation to it, are fully real, even if it is not. It explains that virtual reality may be used to cure phobias — which remains contradictory in any conception for which the virtual is a kind of potential.

Internet technology fostered the environment for virtual work in teams, with members who may never meet each other in person. Communicating by telephone and e-mail, with work products shared electronically, virtual teams produce results without being co-located.