In order to approach an understanding of how the system described thus far produces the "phenomenon" of perception we have to go back to the foundation of what an Entity is and how their Activation leads to meaning. This page is broken down into the four functions of the title, and following their description we may then progress to a clearer definition of Interpretation on the next page, from whence the subject of emergent Dominance can be tackled. Entities  In all Entity diagrams it should be noted that the spatial difference between Entities has no meaning in itself. Within a physical construct, to be sure, there will be a physical distance between the actual Entities, and within the brain axons have to physically traverse that distance. But of course within a computer system, or the general model of Dasein put forward here, such distance has no meaning to the system itself and is, in the case of the brain, an artefact of the medium in which Dasein is manifest. Distance may, however, play a role in limiting the propagation speed of information within the physical body of Dasein, and this shall be considered later. Entity complexes  One class of Entity complex, the Star Entity, has been mentioned before, the analogy to the gravitational pull and the luminosity of a star being most apt to the behaviour of some Entities under Hebbian modification. Star Entities are simply a type of Entity complex that by the nature of what they come to represent within the World, are more often detected by the senses or more readily identified with what is detected than other Entities. Thus, they become relatively more heavily interconnected, and are likely to maintain or gain this material dominance provided the Real World in which Dasein exists does not alter dramatically. This image shows how a Star Entity may appear, functionally speaking, but note that an Entity complex need not be such a large, or small, collection. In practice, the "boundary" between a "complex" and its surrounding Entities is not going to be definite, though one may tentatively define any Entity a member of the complex if it results in the Activation of all Entities within that complex within a certain time period. Activation In the brain, neurons undergo a process called depolarisation which is the propagation of a potential difference along the neuronal axon induced by the flow of ions through the neuron's membrane by biochemical events at a synapse, which is a junction with another neuron. This we shall term Activation, which we define as the general case of information passing from Entity to Entity. Though the neurons within a brain are structurally quite different to the simple diagrams of Entities on this page, they are logically and functionally identical. In the brain there are, however, in addition to positive Activation junctions, also negative, or inhibitory, junctions between neurons. Inhibition, which dampens Activation is most likely an important controlling mechanism in a system which, being governed by feedback loops, is quite likely to run away without such checks. Logically there is perhaps no need, since the absence of Activation provides the same logical result. Ultimately, it is likely to be a question of contrast, where inhibitory signals serve to remove the "fuzz" and highlight stronger paths of Activation, this is something that experimental testing can spend time investigating.  The upshot of Activation is a wave of information that flows through the filter dependant on the input signal. This image crudely demonstrates the traditional concept of the propagation of information through a neural network. Note that following Activation, neurons in the brain undergo a period of refraction where, for a while, they cannot be re-Activated, here shown as the Entities turning orange. In the biological brain this is an artefact of the physical and energy limitations of the system, which disappear in an abstracted, programmed, model. However, refraction does serve to prevent the backwards flow of information which is in most senses desirable because generally it is not wished for information to return to the sensory origins. Also, the image only exhibits binary switching, the Activation of an Entity is either all-or-nothing. In the brain, neuronal action potentials are also all-or-nothing, but this is just propagation of the signal, the Activation itself is very much an analogue event that comprises various excitatory and inhibitory signals that differ in magnitude and temporality, the summation of which may or may not lead to Activation. This is almost certainly a necessity of the system, as it allows finer discrimination between various sensed data, both in space and time within the World. Issues such as refraction, Activation times, switching times, inhibition and so on are certainly difficult to address in practice, and impossible to speculate at without a specific physical model in mind. In the end, such consideration goes beyond the immediate goal of describing a generalised model, but should play a very important role in the construction of that model. Temporal stability Given the above, we can now envisage a situation where an Entity complex becomes Activated because it is representative of a Thing of the World that has been detected, and remains in a continuous state of Activation because the Thing continues to be detected. Now whether this continuous Activation takes the form of waves of Activation and refraction, or a persistent uninterrupted Activation depends entirely upon the system in question; but this should be a property of the system. The continuous Activation of a complex of Entities we shall term Temporal stability, for this group is interrelated and encountered within-the-World in such a way as to have a "presence" within the World of Dasein beyond the transient Activation seen above. Temporal stability of certain regions of the brain given certain stimuli is a core and well documented feature of fMRI study of the brain. Summary
Created 16th July 2009 Revised 23rd July 2009 |