A UNIVERSE OF PERCEPTUAL ENTITIES

Multiple memorized and recorded observations of the cosmos... by countless numbers of us sentient awarenesses... has induced the realization that it is populated by an infinite number and variety of distinguishable entities. Introspective comparisons of sets of individual physical instances of these entities... or the carefully constructed records thereof... results in the observation that certain perceptual and conceptual similarities exist. We attempt to group things in various ways, according to whether or not we judge them to exhibit particular properties, and label the collections with such words as 'round', 'square', red', 'blue', 'ancient', 'opaque', 'sharp', 'fuzzy'. 'microscopic', 'extra-terrestrial' ...and so on....and so on... Almost without exception, the things we focus our attention on will present with varying degrees of any particular property we select, so that a decision will have to be made, as to whether or not the thing under consideration possesses an acceptable level of the property being investigated. Sorting a population of entities that possess varying proportions of 'roundness', 'squareness', 'blueness', and 'redness', will require some sort of consensus criteria as to when something is to be deemed more 'round' than 'square', or more 'red' than 'blue'... and it doesn't much matter whether we are considering the light signatures of stars, or the political affiliations of potential voters.
This universe of entities appears to be infinite and beyond any enumeration total, as it changes and continues to grow in some regions and diminish in others. The phenomena involved in contributing to this dynamic situation involve such processes as... galactic and stellar evolution... biosphere reproduction and death... the technical ingenuity of living things... the creation of memories and records...etc...
We sentient beings...by means of memories and communal records... can only ever be aware of an approximate subset of this universe...either in the present...or at some time in the past. Even then, they are transient and fleeting phenomena, as entities disintegrate and vanish, and dedicated searches and improving technology reveals more and more hitherto unknown existential 'things', and the absence of those previously recorded.

A CENTRAL CONCEPTUAL PREOCCUPATION

Sentient beings...even those which we anthropocentrically 'dismiss' as having 'primitive' intellectual abilities... probably use a significant portion of their information processing capacity developing and understanding classification systems. Living things, non-living things, technological artifacts, ideas, languages, and even words themselves, are all partitioned...according to one strategy or another... into groups that are deemed to be similar and capable of being described by a set of socially agreed criteria. For instance, every 'common-noun' type of word in a language, is a label for a set of (linguistic) constraints that must be at least partially understood, before any sensible communication can result from its usage. When we observe an environment that is familiar, we have already analysed, researched and cataloged most of the entities that populate it, so that we do not have to consciously focus particularly on many specific aspects. If we were raised in a rural environment, for example, we would quite naturally be aware of a wide range of animals and crops and agricultural chemicals... and so on... but very unsure about what was what backstage during the theatrical production of a play or opera being performed in a major metropolitan city. It is only when we are cast into a foreign environment...another society, industry, ecosystem, or the like... that we realize the urgency of having to identify and classify, if we wish to exist and survive there.

LINGUISTIC CATEGORIES

For the purposes of social communication, entities with characteristics that are perceived to be the same, are associated and grouped into categories that have fuzzy boundaries and multiple identifying 'names'. Seemingly unique characteristics of a perceived configuration of the universe are abstracted, memorized, and even recorded as a named specific phenomena. The abstracted memory content or recorded details can thereby be made available as a comparison template for subsequent perceptions.
Since each and every awareness has the capacity to abstract what characteristics appear to it to be essential, one particular existential configuration may end up being associated with several different names, and several different configurations could well be labeled with the one name. Thus in English for example, we are all familiar with the situation whereby the recollected template of a violent meteorological event of high rotational winds and torrential rain might be labeled variously as a 'storm', 'tempest', 'hurricane', 'cyclone' or 'typhoon'... and how the word 'food' could be associated with a wide range of dubious materials, by human grouping agencies with very biased perspectives. These linguistic labels, which act for the most part as general social communication elements, are usually imprecise and rarely subjected to intense analysis. For example, we could use the the remembered pre-school criteria for 'duckness'... a feathered, egg-laying, bill-beaked entity, that could fly, paddle and quack... for describing the antics of one such perceived entity seen amusing itself on a pond. In reality, of course, because of the inclinations of all natural species to hide, deceive and camouflage, even if it looked like a 'duck', walked like a 'duck', and quacked like a 'duck', it still might not in fact be a 'duck'. The phenomena of robotic decoys, impersonation, false passports, spy agencies and PR companies are all ample testimony to that.
It is an on-going function of language and communication to facilitate the evolution of such linguistic categories, so that for pragmatic reasons, they are at least similar and sophisticated enough, for the interchange of reasonably sensible and verifiable information.

LOGICAL PARTITIONS AND COUNTING

The idea of a 'thing' or an 'entity' is initially conceptualized around the perception of some sort of co-ordinated integration. So that 'river', for example, is the word that is used in casual communications to suggest some form of a large flow of water from elevated terrain, which is channeled down thru a landscape to some extended storage reservoir. The primary value of this conceptualization is the knowledge that it conveys about the existence of volumes of flowing water, and the survival implications of such a system to living beings. Eventually, the very 'thingness' of such perceptions, induces the mathematical ideas that such entities have a 'oneness' and are thereby eventually countable.
Once the idea and intention of counting the members of such groupings is entertained however, specifying the boundaries of such groupings, becomes an issue of the logic of 'The Law of the Excluded Middle', whereby a statement about group membership is either true or it is false and there is no 'middle' option. In order to count an entity as belonging to a group or not, a decision has to be made. A statement claiming membership must be true, or a statement claiming membership must be false. There is no logical or linguistic half-way house.
The reality is however, that the boundaries of sensory and perceived group similarities are not logical, but determined by sensory, conceptual and technological precision. Countability in the physical domain is not established by logic, but by pragmatic linguistic criteria and adequate physical measurement. Whether an entity can be counted as 'hard' or not relies on established physical standards of hardness, and the sophistication of the technology used to measure it.
Whether an entity can be counted as 'living' or not depends upon observations and measurements that are made to determine whether or not it conforms to a particular established set of criteria. It is these measurements that determine whether the entity can be included and counted into the category of 'living' things and not logic. It is the contrived criteria and the sophistication of the measurement technology that determines whether something is 'living'or not.
Attempts at 'classification' of this universe... by 'defining' countable partitions of it... are faced with the unavoidable circumstance of trying to describe properties that cannot be unambiguously specified. The focus of what is perceived to be essential in order to define what is 'living', shifts unstably as new technologies and previously unknown candidates materialize. The 'definition' that an individual 'living' entity belongs to a named and identified breeding population...called a 'species'... fails to be appropriate in many circumstances, so that the point of trying to promote it becomes less than helpful.

THE PRAGMATIC PURPOSES OF CLASSIFICATION

All living things have needed to develop methods and systems to discriminate elements of their environment in order to react to changing situations and enhance survival prospects. The need to conceptually classify things into groups and simplify reality, is driven by the advantage of being able to communicate about existence and understand enough to be able to use co-operation to assist in surviving its hazards... in short, to be able to find food, avoid catastrophe, reproduce, and exploit the environment.
From birth, by means of the on-going process of communicating our classifications by a symbolic language, we gradually assume we understand what is meant by the use of such invented symbol-names as 'clouds', 'rivers', 'stars', 'stones', 'hot', 'cold', 'trees', 'plants', 'animals', 'insects', 'fish', 'birds'...and so on...
From a very early age, practically everyone quickly appreciates... through usage and context... the broad-scale classification differences conveyed by these terms. Detailed subdivision of the innumerable entities that could be embraced by such partition-words however is often very limited unless particular expertise is in evidence. Fishermen would usually be able to identify numerous sorts of fish, but be unable to recognize more than a handful of common trees, or a single type of rock. Astronomers might be able to identify every object in the sky, and yet know nothing whatsoever about microbial fauna and flora.

The purpose of classification... as a very pragmatic and convenient method for simplifying and managing complex situations... is frequently associated with one or more of the following factors:

① Communication: where every-day language and research/review discussions are facilitated by the use of 'class' or 'common' nouns...either those inherited by widespread inter-generational usage, or invented by a discipline of interest.
eg daily discussions, scientific research papers, newspapers, legal documentation...

② Efficiency: whereby the classification and location of appropriate utensils, equipment and supplies is an essential feature of many types of system and organization.
eg kitchens, operating theatres, emergency vehicles, workshops...

③ Counting: which is only possible and sensible if clear classification criteria exist as to what exactly is going to be recorded. It may at first glance appear a trivial consideration...to count the number of apples in a bowl...but when one is confronted with the task of getting a robotic machine to count only apples, and not nashi, nectarines, or quinces, the exercise takes on an entirely different perspective.
eg packing sheds, census and voting operations, fish quota, traffic violations...

④ Sorting: which is a vital process when trying to deal with very large collections of undifferentiated things. A finite set of classification criteria need to be formulated so that the storage silos contain manageable quantities of objects with very similar properties.
eg recycling depots, archaeological sites, espionage data...

⑤ Retrieval: as the ultimate goal of many classification and storage systems. The criteria used will need to be to be codeable in a manner that will expedite recovery.
eg libraries, warehouses, image data bases, files, phone books...

⑥ Prioritization: whereby lists of considerations are ordered as a convenient... if not vital... procedure in a range of human activities involving a variety of conditions, life choices, circumstances, threats, and time management concerns.
eg triage, security, emergencies, business management...


From an anthropocentric perspective, the universe of countables would probably have to include at least the following classification categories...
Ⓐ Sensory perceptions: of touch and taste, sight, sound and scent...
such as 'rough', 'smooth', 'sweet', 'sour', 'loud', 'soft', 'fragrant', 'foul', etc, ...

Ⓑ Physical entities: of biology, geology, astronomy, chemistry and physics...
such as 'plant', 'animal', 'sedimentary', 'planet', 'galaxy', 'atomic', 'molecular', etc, ...

Ⓒ Conceptual structures: of language, art, symbolism, theory and logics...
such as 'aural', 'linguistic', 'symbolic', 'neolithic', 'religious', 'hypothetical', etc, ...

THE FORMULATION OF CRITERIA

Classification criteria are formulated using concepts assumed to be relevant to the purpose. Those definitions which concern conceptual entities like 'number-counts' or 'propositions' or computer language 'elements', can indeed be constructed unambiguously, and applied logically so that disputation and disagreement can be settled by 'the law of the excluded middle'. In the abstract conceptual system of number-counts for example, class definitions for 'integer', 'rational', 'fractional' and 'complex' are meticulously contrived so as to ensure that any specific numerical entity can be unequivocally assigned membership or not. Controversy is minimized and for all practical purposes non-existent. Entities can be deemed to be either included or excluded from a particular class, and the conclusion defended on logical grounds as indisputable.
This is not the case for attempts to classify existential entities... like books, elements, stars, animals or plants... because the definitions are inevitably debatable. These criteria will unavoidably be influenced by individuality, bias, pragmatism, convenience, and political expediency. Given a huge random collection of books for example, if the purpose of sorting them is to create a reference library... where the information in those books can be retrieved... the the classification criteria will be formulated around such factors as 'author', 'genre', 'topic', and 'age', rather than 'color', 'weight', 'material' and 'flexibility'. As well as that, for practical reasons, the number of 'classes' formulated would need to be finite, so inevitably, biased decisions will have to be made about where to locate ambiguous examples.
Technology might well often be of assistance in classifying by 'weight' or 'colour' or by bar-coded computer based alphanumeric labeling, but in that case, the chosen criteria will have to be programmed somehow into the computer decision making system. Whether the classification decisions are made by humans or computers, the criteria can never be implemented without error, and thus a level of uncertainly can never be eliminated.
Taxonomic structures attempt to order things by defining groups or classes in a manner that is driven by what properties are thought to be significant. Whether such considerations as morphology, environment, mode of locomotion, mass, chemical composition or electrical charge are deemed relevant and factored into a system, is determined as much by the inclinations of the system creator than by any constraints of logic. Debate and lack of unanimity about priorities of classification properties is absolutely inevitable. Systems which attempt to define categories of biological entities... into which specific examples will unambiguously be deemed members... will probably always struggle to gain general acceptance, because as time and technology brings new revelations, the priorities and understanding of those trying to do the classifying will undergo continuous metamorphosis. As well as that... as in the case of fossil entities... classification will more often than not have to be done on the basis of a reduced and incomplete set of evidential factors. Conclusions about group membership will usually be based on deficient evidence and as a consequence only carry with themselves a degree of probability...

PHYSICAL SYSTEMS

In order to create a classification system for certain physical phenomena...like stars, rocks, or clouds...the core decisions that have to be made involve deciding what groups of entities are to be included, how any subset partitioning might be organized, and if any grouping of groups could be appropriate.
In an astronomical system, for example, as well as the stars and the moon, is it appropriate to include meteors, satellites and aurora? As new objects are discovered, how will such things as 'neutron stars', 'black holes' and 'quasars' be incorporated? Would it be helpful to group entities into 'blue' things, or 'moving' things, or 'fuzzy' things, or 'bright' things...and so on...? Is it possible and sensible to group some of the 'galaxies' into a 'spiral' partition and others into an 'elliptical' partition?
Whatever choices are made, they are made in the light of what options are known about at the time, and it is virtually certain that as time passes, newly discovered entities will oblige a re-evaluation and restructuring of the initial choices. Early elemental chemical classification had no partitions for 'helium' or 'uranium' because their existence was barely even suspected. The first attempts at classifying rocks and geological structures had not even thought of the 'igneous', 'metamorphic' or 'sedimentary' partitions.

TECHNOLOGICAL SYSTEMS

More that any other type, these illustrate the necessity that any system at all must be flexible and adaptable and be able to evolve as new and different entities have to be considered. Human technology creates new devices seemingly endlessly, and so classification systems for devices in such arenas as medicine or telecommunication, need to be capable of revision on an almost real-time basis. Yesterday a cryogenic device for ablating heart tissue did not exist...today it has been trialled successfully and needs a name invented for it, and a classification category assigned, so that it can predictably appear in a medical catalogue. Although for many systems...such as libraries... building in some sort of hierarchical tree structure to classification subdivisions is still useful, the significant increase of computing speed has enabled many technological systems to utilize a UDI(Unique Device Indicator) strategy, and allocate a single identifying code to each specific device. The web, for example, uses a MAC(Media Access Control) address of six pairs of hexadecimal digits, which provides more than enough unique numerical codes, to label each and every electronic device ever connected to the web.

BIOSPHERE SYSTEMS

When we observe the multitudes of different types of animals and plants in our environment, and note their appearance, behavior and life-cycles, any attempts at classification will immediately be confronted by the reality that there is both a vast diversity of form and structure, that there are innumerable entities in existence that have not been seen and described, and that there are many subsets of similarity.
Comparing these living entities, we might at some times be confronted with extreme differences of complexity, morphology and magnitude, and yet at others be struck by the many ways in which they resemble one another.
The difference between a microscopic archean prokaryote... which until the invention of the microscope we did not even know existed... and a jurassic brontosaurus... which we inferred must have existed once we realized what fossils were... is so great, that finding any similarities involves considerable ingenuity.
On the other hand, the similarities between a cabbage and a rape plant, or between an ocelot and a cervil, are so many, that some attention has to be dedicated to determining what significant differences there are.
The formulation of a comprehensive classification system of all living things is an undertaking of bewildering complexity, so far beyond the resources and capabilities of any single awareness, that progress towards its construction can only proceed with the cooperation and consensus input of many, many groups of (scientific) researchers.
Initial attempts would note a range of possible broad categories that seem to offer the opportunity for a degree of simplification... some things move and somethings stay put... some things swim, some things fly, some things walk and some things slide... some things are covered in feathers, whilst others have skin or bark or scales... there are soft-bodied things and things with hard shells... things that are good to eat, and things that hurt... some things are too small so see with the naked eye, and some things existed before awareness was able to introspect.
Many cultural traditional systems have been devised, where partitions of the biosphere life-entities have been based on such considerations as 'spiritual' significance, 'medicinal' value, 'nutritional' importance, and so on, but the most widespread system is a (scientific) attempt whereby attention is focused on morphological factors, to successively define more and more detail, so that a 'tree' structure of branching and linked relationships is formed.
Words like 'kingdom', 'phylum', 'class', 'order' 'family', 'genus' and 'species', have been... and still are... used to denote classification categories of increasing specificity, where the attempted definitions are sufficiently unambiguous, that any particular life-entity can be placed in a particular partitions with a minimum of controversy.
However, any putative biological classification structure will always be subject to revision, rethinking, and reconfiguration, because of...
▶ the developments of new technologies... like computers and electron microscopes...
▶ the discovery of 'new' life-entities... like thermophiles and archaea ...
▶ the discovery of unknown structures... like DNA and black holes and molecular motors...
▶ the re-examination of the function of forms... like 'junk' DNA and mammalian whiskers...
There will never be a set of human defined classification categories, that will enable every living and extinct life-entity to be places unambiguously into a specific partition... but then so what?... no-one can demonstrate 'logically' that 'logic' is the only justification of doing something without disappearing up their own anus.

THE SPECIES DEFINITION ATTEMPT

One of the prime objectives of a biosphere classification system, is to be able to pigeon-hole individual entities...known or unknown...into the conceptual partitions of a hypothetical structure, with the hopeful expectancy that a grand synoptic picture of evolution and life will eventually begin to emerge.
Because a considerable portion of our lives involves witnessing and participating in the life-cycle processes of groups of living entities, we are drawn to the idea that it might be possible to classify such groups of similar entities into a single umbrella category. A 'species' level of classification therefore became an attempt to provide sufficient conceptual containers, so that any particular entity could be unambiguously placed into a named container of similar entities.

A 'species' name might be attributed to an entity-group of biological individuals, that interact behaviorally and genetically, that have a unique evolutionary lineage, and that are morphologically similar enough to satisfy the classification criteria of a human taxonomic authority. It could refer to an evolutionary phase of a set of morphologically similar biological entities, that have evolved by means of a unique system of replication and recruitment.
For a sufficiently small temporal window, a species 'name' might be allocated to a unique morphological and behavioral group of biological individuals, that can be taken to represent the instantaneous phenotype manifestation of a gene-pool lineage. A 'gene-pool' is the time-dependent state of a dynamic group/collection of interactive biochemical entities, that are capable of replication, partition, conjunction and recombination.
A 'species' name might thus be associated with a unique set of characteristics, and any individual deemed to possess those characteristics can be counted as belonging to that entity-group.
This perspective describes the pragmatic operational procedure that is eventually usually applied, rather than paying undue attention to what might happen to be the current or fashionable lines of thinking.
The 'species' label has been driven significantly by the attempt to describe those groups of life-entities that participate in (sexual) reproduction as a fundamental taxonomic unit, but ultimately, it is a bit of a red-herring. Replication and reproduction are significant behavioral properties, and will inevitably be included in the set of classification criteria, but... as in the case of dead or extinct examples... they cannot be the only criteria, against which all life-entities can be evaluated.

ANALYTIC SYSTEMS

Mathematics evolved as an intellectual exercise manipulating the conceptual counts of classified entities. Entities such as fellow humans, animals, plants, rivers... were classified and counted , and the recorded or memorized totals manipulated to derive further information, that can justify management statements.
"That group of individuals was greater than this group of individuals."
"There is enough meat on this single animal to feed the entire group."
"We do not have enough spears for everyone."
From such primordial introspective thoughts, the entire abstruse intellectual edifice of mathematical relationships, theorems and procedures has complexified. Because the entire structure is contrived to be free of contradiction, it has come to assume a mantle of 'certainty', in the sense that any of its assertions and implications can be placed before an evaluation forum, and justified by formal argument. By never abandoning the core tenet, that 'a statement cannot both be true and false at the same time', all the statements of mathematics can thereby be deemed to be 'certain'. Hypothetical objects...like integers, integrals, sets, algebras, geometries, and so on...can be absolutely and unambiguously defined, to that universal consensus agreement is possible by means of meticulous and justified argument.
Any assumption that this situation can be carried over into classifications in the real world is entirely misplaced. The universe is far too complex and chaotic for the unambiguous classification of the myriads of entities constructed from myriads of other entities. The classification of entities in the real universe can never by monitored by the logic of non-contradiction.

THE GENERATION OF AUTHORITIES

Because of the immensity of many attempted classification systems, pragmatic reality has fostered the evolution of reference authorities.
At one end of the scale, a grandparent can explain to a grandchild the difference between a fly and a wasp, and at the other end, academic entomologists can discuss at great length, the range of evidence for the inclusion or otherwise of a particular specimen in a predefined genus.
Such reference authorities provide an immediate starting point for individuals being confronted for the first time, by situations where classifications are necessary. It is just not possible for single (human) awarenesses to create classification systems for every situation that they find themselves in. Library catalogues, phone books, dictionaries, museum displays, and so on, are all the pragmatic starting references for anyone confronted with dealing with the entities they each cater for. The individual makes use of the classification strategies and design of such pre-created systems, and then judges for themselves the usefulness and relevance of the exercise.