The domain of existence is that which thought structures. This is not to say that thought creates the cosmos in any way, but that the term existence refers to the generalized structure or model that an awareness has created for itself. The process of thought's participation in the cosmos results in an awareness of certain forms and continuities whose domain is what is called existence. Within this existential environment, entities are said to exist. Existence is the ontological consequence of thought. All entities are on the cutting edge of existence where the certainty of ultimate oblivion is distributed by the random perturbations of nature.

The property of existing is attributed to a structure or form by an awareness abstracting it from perceptual experiences. To ascribe existence to an entity is to identify it as a one. Sufficient evidence needs to accumulate in the memory structures of the awareness, before any inductive processes can evaluate the probabilities as to the significance of the perceived form and hence the pragmatic decision to assume the existence or not of an entity. Most physical entities in the immediate every-day macro world are deemed to exist on the basis of sensory perceptions. The existence of an aircraft in a control zone is confirmed visually. The existence of a rare bird is recorded by its unique song. An enlarged prostate is detected by the sense of touch. However, detecting the existence of many entities... like sub-atomic particles, postal systems and underground resistance groups... will usually take much more than a single observation.

An entity existing for one individual or group, may not exist for another. A newly discovered oil reserve or goldfield will only exist for the discoverers. A spy will only exist for the side doing the spying. The perceptions, pains and memories exist for the individual alone. Knowing about the pains and memories of another individual does not thereby make them exist for you.

Ranging from an almost universal agreement that the sun as an entity exists, thru the uncertainties about many biological species and astronomical objects, to the improbabilities of fairies and souls, attempted classifications of entities... as existing or not... will forever be subject to reappraisal. We recall that there was a mantis and a caterpillar on the swan plant barely minutes ago and now there is only a mantis. Perhaps the caterpillar was eaten by the mantis. We assume from the fossil record that dinosaurs have ceased to exist, yet there is always the haunting doubt, that perhaps there is a living example somewhere. The entity which we reassured ourselves existed a moment ago, may well not exist now, and the presumption of extinction has been premature on more than one occasion.

The most difficult phenomena in nature that a self-awareness has to cope with, is the unexpected event whereby a familiar and valued entity... living or otherwise... ceases to exist. Many humans find this so incomprehensible, that an after-life is postulated, in an attempt to render the stark realities of the cosmos more acceptable.