The central concept of semiotics is the sign. This comes from Locke (who equated it with words and ideas) through Peirce, who generalised it to the inorganic world, and Saussure (who thought of the sign as an arbitrary pattern in the context of language). For Peirce, a cloud in the sky was a sign that it was going to rain which provoked a disposition to respond by taking out one's umbrella. However, curiously, the absence of something would be just as much a sign as the presence of something - a cloudless sky would mean a fine day so that one would take out one's parasol or sunhat, a different disposition to respond. The sign, Peirce also said, is only a sign if it is interpreted as a sign - so if one does not look at the cloud, or the cloudless sky, there is no sign.

The confusion about what constitutes a sign makes one wonder whether there is something fundamentally wrong. Is the whole idea of the atomic sign a mistake? Are not 'signs' only meaningful in the context of the total organisation of the individual's 'knowledge-structure' and of the total relevant environment as perceived by the individual ? The key questions then would be: How is the 'sign' marked off, distinguished from the totality, that is, how does the subject decide where to focus his attention, whether in regarding the external world or regarding his own interior world ? What makes for the 'salience' of the sign ? How does the 'sign' modify the subject's internal mental [ neural ] organisation, that is, the mode of interpretation of the sign ? This brings one very close to issues about the nature and process of perception.

But what then is the sign-process? The sign must, in some sense, be perceived before it can function as a sign by being matched with its hypothetical interpretant (a pre-existing idea or concept, tendency to action or whatever an interpretant is supposed to be). Perception thus is essential to, and prior to, the sign-process. Peirce and Morris touched very briefly on this: Morris simply noted "the difficult question as to whether or not perception is to be regarded as a sign-process"(34) but Peirce more categorically said: "The immediate object of all knowledge and all thought is, in the last analysis, the Percept".(1960 IV:424) The relation between perception and the sign in Peirce's approach, and that of others, is unclear and it seems necessary to examine much more profoundly what is involved in perception.

Perception has been a subject for speculation and controversy for thousands of years. More recently the topic has been a main concern of psychologists and neurologists taking over from the philosophers who had a monopoly of it for so long. There are varying accounts of the nature of perception. Neisser has written most penetratingly as a psychologist:

"Discussions of the object concept are bound to be misleading .. They implicitly suggest that the function of perception is to inform us about things as mere objects .. far from being the whole truth. in the normal environment most perceptible objects and events are meaningful. .. These meanings can be, and are, perceived. .. These perceptions [of meaning] often seem very direct .. we become aware of the meanings without seeming to notice the physical details that provide evidence for them. [the meaning e.g. of a smile] .. This aspect of perception has long been a theoretical stumbling block for psychology. . The meaning must be supplied by the perceiver after he has registered the stimuli. Why, then, do introspective reports suggest that the meaning is available first, and the stimulus details later, or not at all? .. Perception of meaning .. depends on schematic control of information pick-up."(Neisser 70 ff.)

One can set beside this the equally searching ideas of Llinas, as a neurologist:

"In order to see one requires first to have moved within the world and to have established, via the use of natural coordinates, the properties of objects with respect to our own physical attributes (the weight of each object, its size with respect to that of our body, etc.). It would be clear then that it is only through the ability that our brain has to transform measurements in one set of coordinates (the visual system) into comparable sets of measurements (visually-guided motor execution) provided by other sensory inputs (for example, touch from fingertips) that one can truly develop the necessary semantics to be able to understand what one sees. The point is that understanding the functional connectivity of the visual system is not sufficient to understand vision. Rather, putting vision into the context of coordinates that are intrinsic to the body is the essential step needed to 'make sense' of the visual information."(Llinas 352)

But perception is not a series of isolated events. It is a continuous process producing continuous change in the perceiver.

"There is other evidence .. that each new experience is sorted or classified while it is being recorded. Similar experiences seem to be somehow united or associated in the [temporal] cortex."(Penfield 298) "Experience is remoulding us at every moment. whilst we think, our brain changes."(James 234) "The perceiver engages in an act which involves information from the environment as well as his own cognitive mechanisms. He is changed by the information he picks up. The change is not a matter of making an inner replica where none existed before, but of altering the perceptual schema so that the next act will run a different course."(Neisser 57) "perception is a continuing interaction with the social and natural environment."(Neisser 195)

In this continuous process of perception, the perceiver is creating and constantly updating a model of the world and of himself in the world.

"The picture [built up by research] .. does suggest that the cerebrum has at its disposal a map of external events expressed by the temporal and spatial distribution of excitation in the receiving areas"(Adrian 237) "these transformations may be viewed as utilising sensory input to modify ongoing internal functional states. These internal functional states are then homomorphic with external reality. The sensory input feeds and modulates an internal state of intrinsic origin."(MacKay 1987) "The real experiences get sifted from the mental ones, the things from our thoughts of them .. and precipitated together as the stable product of the whole experience-chaos, under the name of the physical world."(James) "what is thus true of another's thought is equally true of the perception of the outer world in general .. to perceive the universe we must construct it in thought".(I 219) "The inputs are thus used to create a 'portrait' of the inner and outer sensorium. This amounts to an organising system that is being constantly updated by fresh information and which maintains a 'conditional readiness' of the organism in relation to strategically related environmental demands. .. The stable model is attributed the status of reality".(Crook 388-390)

But how can such a model of the external world be recorded in the individual's nervous system? The answer many authors give is that it is modelled on and in the body itself. At the philosophical, psychological level in his Phenomenology of Perception, Merleau-Ponty puts it this way: "Every external perception is immediately synonymous with a certain perception of my body.. The theory of the body schema is, implicitly, a theory of perception."(Merleau-Ponty 206) As a neuropsychologist, Lashley made the idea more specific: "The perceptual processes in vision may be far more dependent upon integration with the postural-kinaesthetic system than we ordinarily assume. .. It is not impossible that all the spatial characteristics of vision are .. dependent upon integration with the postural system. It may be that we shall have to seek the source of visual percepts in the integration of these two systems."(Lashley 432) and Sommerhoff made the idea even more specific: "Since the body functions as an important frame of reference in the perception of spatial relations, the brain's internal representations of the external world can be complete only to the extent to which they are integrated with the internal representation of body posture and movement."(Sommerhoff 234)

Another important idea is that perception is interpenetrated with action and indeed that perception and action have very similar characteristics. "Perceiving is not the only activity that depends on spatial and temporal continuities. Actions and movements have the same character"(Neisser 51) "action is organised just like perception, guided by expectancies that in turn are altered by consequences.. Although perceiving does not change the world, it does change the perceiver. (So does action, of course)."(Neisser 52) "perception and action not as separate but as closely interrelated processes involving the same higher level mechanisms and structures"(MacKay 198)

Perception is inextricably linked with the focusing of attention: "Attention is nothing but perception; we choose what we will see by anticipating the structured information it will provide.(Neisser 87) "our ability to focus on any particular aspect of the external world requires the 'extraction' of the object or invariant from the perceptual background. This object-background separation, similar in every way to attention,. in man, and probably in other higher mammalian forms,(Llinas 354)

All these features of perception are the product of a very long process of evolution, going far back before the emergence of Homo Sapiens and no doubt before the emergence of the vertebrates. Genetic factors play the principal role in organising the perceptual capacities in animals as well as in humans. McFarland, in this connection, refers to the work of von Uexkull: "whose ideas on the perception of animals much interested the early ethologists, particularly Lorenz. Von Uexkull proposed the concept of the Umwelt, the subjective phenomenal world as the animal itself sees it in contrast with the actual environment. He regarded the first task of research into the Umwelt as identification of each animal's perceptual cues among all the stimuli surrounding it."(McFarland 271)) All perception is guided and governed by phylogenetic as well as ontogenetic predispositions: "Every sensation, even the 'purest', must .. be regarded as an interpretation of an event in the light of the past experience of the individual or the species."(Hayek 166)

From this survey of views on the nature of perception, one can draw the following points:

1. Perception cannot readily be analysed sequentially from the object, through the sensory channel to the 'mental' pattern of the concept, and interpretation of the concept. The perceiver brings a prior structure to each act of perception and the act of perception is directed (as an aspect of attention), not simply a mechanical pick up of whatever information there happens to be.

2. Perception is not intermittent but continuous, producing continuous change in the perceiver. The prior structure which the perceiver brings to each act of perception is an elaborate neural structure which in some way constitutes a model of the expected environment as well as a model of the individual himself, body and mind. Each new perception modifies the total model.

3. The creation of these models is closely linked, perhaps directly dependent on the representation in the brain of the perceiver's own body. The body image serves as an organising construct from which all other perception derives. The structure of oneself is the means by which we order our experience of the world (the structure of oneself including the permanent awareness of oneself as body plus accumulated experience, and attitudes).

4. Perception is associated with action in many different ways. The act of perception is itself a motor performance, requiring direction of the head, the eyes, even the bodily posture. And perception is closely involved with the determination of patterns of action following perception. Not all perception leads immediately to action: reading a text may modify the reader's 'ideas', produce neural changes, without resulting in any overt motor action. But, in evolutionary terms, perception developed to serve the need for action, for response to the environment, and the structuring of perception and of bodily action are likely to be very similar, complementary and interlocked.

5. Both the structures of action and the structures of perception are something that we have inherited, that evolved long before Homo Sapiens. It is likely that our organisation for perception and for action are the same as or very similar to those of other primates, and probably much further down the evolutionary scale. Signification for us and for animals must be a very similar process.

Now what bearing has this view of perception on semiotics, the science of signs, communication? What distinguishes perception from communication? Here we encounter problems with the vagueness of terms: if we identify communication with all 'sign-processes', messages from the environment, then perception and communication become identical. The cloud communicates information about rain to us. This, however, does not seem a very helpful use of 'communication'. The narrowing down of the concept seems to require that we should call communication only the transfer of meaning from one animate creature to another. Our awareness of the other extends not only to awareness of them as a particular body but also of aspects of their self, perceived through language and through interpretation of the indicia of the other's attitudes, structure, emotions, character etc. If this is so then the concept of the 'sign' takes on a quite different property: it will be because one human and another, one animal and another, share similar behavioural organisation, perceptual organisation, ultimately neural organisation, that an action of one can serve as a sign conveying meaning to the other. The meaning of 'sign' then has to be deepened to recognise it as the product of a much more complex shared structure.

A totally unchanging environment communicates nothing. Perception is perception of change in the environment.To perceive change, the perceiver must have retained the pattern of the normal,the stable, the usual, the expected. A sign, one might say, is a perceived change in the stable, expected, perceived environment. The source of any change may be the inanimate environment (wind, rain, cloud), the animate environment (conspecific or other specific), the individual human environment, or the social environment. Language can be classified as perceived change in the human environment.

To make possible this process, the perception of change, there must be appropriate neural organisation, a neural record of the expected environment. The perceptual capacity of the perceiver derives from the model it retains of its environment and of itself as acting within that environment. A pattern is what we see as a pattern. What we see as a pattern is what we can see as a pattern. Patterns of things are related to the possible patterns of our perception.

Our brains must be structured in terms of the usual or expected environment and perception is the result of interaction, or matching between the expected environment and the current environment by which change is detected. There must then be restructuring in response to the perceived change, possibly not as a separate process - the awareness of the perception may in fact be the restructuring. Perception would then be a direct reflection, an internal representation of reality, internal ordering guided by external ordering.

For the human or any animate creature, the interaction is between the given environment and the given inherited neural structures which make perception possible. There is no reason to believe that there is any gap between perception and the world, or language and the world. Our perceptual capacities evolved to coincide with the structure of the world as we find it, because perception evolved in the service of effective action for survival. Perception evolved from the organisation of action, communication evolved from perception, language evolved from communication.

Perhaps we should seek to construct a theory of signification [the extraction of meaning] rather than a theory of signs. We should not conceive of the neural processes as successive processes of coding and decoding but rather as transformations which result from propagation of the input through a complex system (the total network of neurons). Rather than serial processes, something much more like the ideas in parallel distributed processing will be relevant. Connectionism leads away from the atomic sign, the atomic idea, the atomic concept, to the complex global modifiable network, producing expectancies which control perception, that is, how changes in the environment are processed from moment to moment.