Integrative Levels Classification project scheme how it works León Manifesto references

How ILC works

Examples updated to ILC 1 (November 2010)
Version updated to ILC2 available


classes ; free relationship ; facets and categories ; passive facets ; common facets ; place of definition of facets ; subfacets and subfoci ; conjunctions ; spans ; typical subclasses ; deictics, favoured class and special schemes ; viewpoints ; disciplines ; fiction


Unlike most library classification schemes, ILC classes do not represent disciplines and their subdivisions, but phenomena of the real world.

Phenomena are listed in order of integrative levels. As classes are basically represented by letters, this means that simpler phenomena, like atoms or molecules, are represented by low letters like c, d, e, f, while more complex and integrated phenomena, like societies and cultures, are represented by higher letters such as s, t, u, v:

	d particles
	e atoms
	f molecules
	g bodies
	h celestial objects
	j lands
	k genes
	l bacteria
	m organisms
	n populations

Further letters, written in low cases, mean subclasses, namely kinds of their main classes:

	m  organisms
	mf 	mushrooms
	ml 	algae
	mm 	mosses
	mp 	vascular plants
	mq 	animals
	mqm 		mollusca
	mqr 		arthropoda
	mqrh 			crustaceans
	mqri 			insects
	mqv 		chordata, vertebrata
	mqvh 			bony fish
	mqvl 			reptiles
	mqvo 			birds
	mqvt 			mammals

In this way, a longer string means a more specific phenomenon (as in traditional library classifications). At each degree of specificity, whenever possible, phenomena are listed in an evolutionary sequence, or increasing logical depth.

In some (not common) cases, more than 26 subclasses of the same class are needed. Zoology teaches us that mqvh bony fish has more than 26 subclasses. To cope with this, some less relevant subclasses can be expressed with the "empty digit" z, giving them the same specificity as the adjacent classes, despite having a different number of digits:

	mqvhx 		tetraodontiformes
	mqvhxzf		pleuronectiformes
	mqvhxzs 	scorpaeniformes
	mqvhy 		perciformes

Free relationship

When several phenomena occur together and are considered in generic relationship between each other ("generic phase relationship" or "free relationship"), they can be simply listed together, separated by a blank space (free classification in Gardin's terms). It is usually preferable that they be written starting from the highest integrative level (namely the highest first letter) and going on with more and more low levels, in the reversed order of the schedules:

	mqvt mf hU	mammals : mushrooms : the Earth
	n mqvt      	populations : mammals

Facets and categories

Facets are more specific relationships, representing typical aspects of a phenomenon in connection with other phenomena. Facets of organisms are growth stage (embryo, larva, adult), organs (heart, lungs, kidneys), and sex (female, male); facets of music are players (persons, groups), instruments (drums, guitars, trumpets), and genre (root, jazz, rock).

As these examples show, facets change according to the different phenomena. However, they roughly belong to a limited number of general categories, according to their syntactical relation to the phenomenon (sometimes also described as their role or, in linguistics, their case or complement). General categories, and the corrisponding facets, are represented by numerals (where needed, two or more digits can be used to define a more specific facet):

	0  considered under aspect, modality
	1  at time, in sequence
	2  in location, context
	3  through change, transformation
	4  of material, constituents
	5  with organs, parts
	6  from origin, source
	7  for function, to destination
	8  having pattern, about topic
	9  of kind, quality

In music, composers are origins, hence they are facet 6:

	xm music
		xm6 music composed by ...
			xm6Ybach music composed by Bach
(As composers are individual humans identified by a name, the name itself can be used as a subclass, preceded by the deictic Y meaning "proper name".)

In animals, geographical distribution is a location, hence it is facet 2:

	m  animals
	m2 	animals in areal
	m2e 		animals in Europe
	m2o 		animals in Oceania

while sex is one possible form of the organism, hence it is facet 9:

	m  organisms
	m9 	sex
	m9f 		female organisms
	m9m 		male organisms

Facets of a given class also hold for all its subclasses:

	mqm9f   female mollusca
	mqri9f  female insects
	mqvl9f  female reptiles

(unless another facet of the same category is defined at a subclass, hence they can be described as cascading facets each holding at a different degree of specifity).

When more than one facet are expressed for the same phenomenon, they should be cited in the reversed order of numerals, according to the inversion principle: as 9 is greater than 2,

	mqvl9f2e  female reptiles in Europe

Only when a subject is discussed focusing especially on one aspect, the corresponding facet can be moved before another despite the standard citation order:

	mqvl2e9f  European reptiles, female

The value of a facet can sometimes be left unexpressed. This can be done by a capital X after the facet indicator:

	mqvl2X  reptiles in some region

X is a deictic meaning "something".

Passive facets

Reversed relations, i.e. passive facets, can be obtained by prefixing 9 to the facet digit:

	xm6bach		music composed by Bach (xm96bach in ILC2)
	pY96xm		persons being composer of music (pY996xm in ILC2)

They can be used to put the central topic of a document first:

	n9qvtniok	populations of killer whales
	o9vtniok	behaviour of killer whales
	mqvtniok99n99o	killer whales: their populations and behaviour

as in "Ross sea killer whale distribution, behavior, color pattern, and vocalizations", a 1981 book by JA Thomas et al. classified in BARD.

Common facets

The meaning of some facets can be applied in any main class: geographical location can be a facet of any phenomenon, as can origin. Such common facets are defined at the most general degree, and keep their meaning in all subclasses, except where a more specific meaning is defined (respecting the principle of cascading facets). In order to apply them, one does not need to find them in the schedule of a specific class, as they can be applied throughout the whole scheme. (In other general classifications they are called "common subdivisions" or "common auxiliaries".)

The most general facets are expressed by one digit, while more specific meanings can be represented by a combination of category digits: 16 means "originated/born at time", as 1 means "at time" and 6 means "from origin". Multi-digit facets beginning with 9 are used to express passive facets.

The list of common facets can be seen by browsing the coloured categories on the right of the schedules main page.

In classes where specific facets are defined for the same category, in order to avoid ambiguity, common facets have to be preceded by V, a deictic meaning "general class":

	xm6 [pY]	music by composer (xm96 in ILC2)
	xm6wu		music composed by Wu (xm96wu in ILC2)

	6 [V]		from origin (common facet)
	xmV6wu		music originated by automata (xm6wu in ILC2)

To introduce facets defined at intermediate degrees, deictics VA, VB, VC... can be used. The meaning of facet 6 in each of the following cases is that defined at the class on the right:

	abcde6		abcde6	(abcde96 in ILC2)
	abcdeV6		6	(abcde6 in ILC2)
	abcdeVA6	a6	(abcde900006 in ILC2)
	abcdeVB6	ab6	(abcde90006 in ILC2)
	abcdeVC6	abc6	(abcde9006 in ILC2)
	abcdeVD6	abcd6	(abcde906 in ILC2)

Place of definition of facets

In some cases, the meaning of facets is self-defined at the same integrative level where they occur, called their place of unique definition: for example, gender is defined as such at the level of organisms themselves, while at lower levels like lands or atoms they are nonsense (atoms cannot be female or male!). To express this, the symbol [:] is found in the schedules:
	m     organisms
	m9 [:]    sex
	m9f 		female organisms
	m9m 		male organisms

In other cases, however, the values of facets are taken from a different level of phenomena. Music composers are usually humans, they cannot be atoms or rocks. So the facet of composers in music is defined outside the class of music. Let's take another example: breeding always use as its material some animal: there are no breeded rocks or breeded trumpets, only breeded animals. Hence facet 6 (natural resource) of vo "husbandry" always is some animal mq, and in the schedules can be found

	vo       husbandry
	vo6 [mq] 	of livestock

This means that subclasses of facet vo6 are the same as subclasses of mq, and their notation must be taken from mq (technically, they can be called extra-defined foci, instead of context-defined foci as in the previous example):

	m  organisms
	mq 	 animals
	mqv 		vertebrates
	mqvo 			birds

	vo	husbandry
	vo6 [mq]	of livestock
	vo6v 			husbandry of vertebrates
	vo6vo 			husbandry of birds

In case the related class is unusually not a subclass of the foreseen class, its notaton will be preceded by a V after the facet indicator:

	vo6Vl		breeding bacteria

Finally, some facets provide for relation with any other possible phenomenon in the schedules. Take knowledge. It has an object, which can be expressed by facet 8:

	y     	knowledge
	y8 [V] 		knowledge about object

Actually, knowledge can have any object, so its notation can be built by combination with any other part of the schedules. This fact is expressed by the symbol [V].

	y8e    knowledge about atoms
	y8mqvo knowledge about birds
	y8xm   knowledge about music
	y8y    knowledge about knowledge

Subfacets and subfoci

y also has other facets, including

	y6 [pY] knowledge by thinker...

Now, suppose that we have to build the classmark for "knowledge about music composed by Bach". Component notation is

	xm6bach		music composed by Bach
	y8 [*] 		knowledge about object

but if we simply put them together, we get


which can be interpreted as "knowledge about music, by thinker Bach" as facet 6 of y means author of knowledge, not of music. What we want to express, instead, is that knowledge is about an object consisting of "music composed by Bach". To avoid this ambiguity, we must express that 6 is a subfacet of facet 8, not a facet of y; subfacets are written in round brackets:

	y8xm(6bach) knowledge about music composed by Bach

When indexing deeply specialized documents, the nesting of subfacets can become very complicated: a document entitled "Guidelines on the applications of the environment protection and biodiversity conservation act to interactions between offshore operations and larger cetaceans" would be


To make notation less awful and easier to parse by both humans and computers, it can be "flattened" by writing some facets as separate terms introduced by free relationship:

	t6X8Z ve6Z mqvtn82y68v(3)25c

Facet Z is a deictic referring to the whole subsequent phase, thus avoiding most brackets.

To summarize it, two classes aaa and bbb can stay in these relationships [Gnoli 2007d]:

	aaa bbb		free relationship	  	(free classification sensu Gardin)
	aaaV6bbb	common facet		  	(freely-faceted classification sensu Austin)
	aaa6bbb		special facet of a class 	(faceted classification sensu Ranganathan)


Two or more classes sharing the same syntactical role can be listed in the same order of schedules and glued by the symbols WA, WB, WC... (or &):

	iWAm 	rocks and organisms

This can also happen within a facet:

	y8j   	knowledge about lands
	y8jWAm 	knowledge about both lands and organisms

The upper case following W means the number of letters shared with the previous class, starting to count from the beginning of the classmark:

	abcdWAx = abcd together with x
	abcdWBx = abcd together with ax
	abcdWCx = abcd together with abx
	abcdWDx = abcd together with abcx

In case the focus is a shortened (extra-defined) one, the count starts from the first letter of the original class, not of the shortened focus: in

	ef5 [ab]
x stands for abx.


A consecutive series of classes can be expressed by connecting the notation of the first and the last of them by the symbol W (or %):

	jWm  = jWAkWAlWAm	rocks and genes and cells and organisms

When used in subclasses, by default it introduces a sister class, like in the case of conjunctions:

	mlWp  = mlWAmWAnWAoWAp	algae and mosses (and ...) and vascular plants

In the rare cases where non-syster classes are involved, they have to be listed all by conjunctions, rather than as a span.

Typical subclasses

Some phenomena are of particular interest to human knowledge. Among all organisms, Man is obviously the most interesting and studied in human knowledge. As an anthropoid primate mammal, its complete notation would be something like mqvtgq; but it is helpful that this long notation be shortened, and Man is listed first among organisms as the one most frequently discussed. To this purpose, the class U "the typical" is used as a differentia, meaning "that which we all have in mind":

	h  celestial objects
	hU  	 the Earth

	hk  stars
	hkU 	 the Sun

	j  lands
	jU = j2U1gh  lands of the Earth in Holocene (contemporary era)

	mU = mqvtgq   humans

Deictics, favoured class and special schemes

Some concepts change their meaning according to the context. Examples are the concepts of "next", "tomorrow", "here", "you"... The meaning of "tomorrow" depends on which day is it today; the meaning of "you" depends on whom am I speaking together. These concepts are called deictics and in ILC are represented by upper-case letters (previously Aa, 98, @). Thus:

	b  time
	baU 	 present time

	p  consciousness
	pYA  I, we
	pYC  you

A to T are the favoured host classes or the domain of discourse. They represent the focus phenomena of concern in the present context. This is useful when most expressed knowledge is about a specific domain, so that a special classification scheme can be used instead of the general one. All classes beginning with A ... T are subclasses of the favoured class, either taken from the general schedules (lower case letters, e.g. Abcd), or in turn locally defined (capital letters, e.g. ABCD).

For example, the Dandelion bibliography of facet analysis mostly concerns subject indexing, its subclasses and its facets. In the general ILC schedule there is

	y49xs 	                   subject index
	y49xs(4)  [:]                    with element
	y49xs(4n) 	                         controlled terms
	y49xs(4s) 	                         subject strings
	y49xs(4t) 	                         notation
	y49xse 	                        keyword index
	y49xsef 	                          folksonomy, tags
	y49xsh 	                        controlled term index from a thesaurus
	y49xsj 	                        subject headings
	y49xsl 	                        systematic index, taxonomy, classification
	y49xso 	                        ontology, semantic network

Hence most references in the bibliography should be classified by subclasses and facets of yis. To get a shorter notation, and to get the preferred topics at the beginning of lists, yis is stated to be the preferred class A:

	A 	                subject index
	A4  [:]                       with element
	A4n 	                             controlled terms
	A4s 	                             subject strings
	A4t 	                             notation
	Ae 	                        keyword index
	Aef 	                             folksonomy, tags
	Ah 	                        controlled term index from a thesaurus
	Aj 	                        subject headings
	Al 	                        systematic index, taxonomy, classification
	Ao 	                        ontology, semantic network

Deictics can also be used in combination: AWD "A to D", YX "what individual". The precedence order of their meaning is reversed: Z prevails on Y, X, W, V, U, A-T.


The scheme of phenomena in ILC is intended to be as objective and neutral as contemporary knowledge allows. Of course, one could always claim that this is only one among many possible views of the world, as it happens in any classification; anyway, the scheme is being developed with an effort towards neutrality.

Sometimes, however, there is a need to reflect different and particular viewpoints in classification -- that is, of viewpoint warrant, as Begthol terms it. Examples are the alternative orderings in knowledge of indigenous people, of non-Western traditions, of adepts of some faith or theory, of children, or schemes for special purposes. In the general scheme of ILC, they will usually fall under classes v "cultures" and y "knowledge":

	mq  	animals

	y  	knowledge
	y8 [V]		knowledge about object
	y8mq  			knowledge about animals
	y9c  		popular knowledge
	y9c8mq 			popular knowledge about animals
	y9m  		magic
	y9m8mq 			magic about animals
	ys  		sciences
	ys8mq  			science about animals, zoology

A most classical example reported by Borges and Foucault is the weird classification of animals in a Chinese encyclopedia entitled "Celestial emporium of benevolent knowledge". It will fall under something like

	y9c29r1e  	popular knowledge in China in the Middle Age
	y9c8mq29r1e  		popular knowledge about animals in China in the Middle Age

Now, subclasses of ydxx8mq do not follow contemporary standard classification such as

	y8mqb  knowledge about poriphera
	y8mqc  knowledge about cnidaria
	y8mqd  knowledge about ctenofora

but a very idiosyncratic system, which can be expressed after a colon as it is a subclass of this particular combination of facets:

	y9c8mq29r1e:a  animals that belong to the Emperor
	y9c8mq29r1e:b  embalmed animals
	y9c8mq29r1e:c  animals that are trained
	y9c8mq29r1e:d  suckling pigs
	y9c8mq29r1e:e  mermaids
	y9c8mq29r1e:f  fabulous animals
	y9c8mq29r1e:g  stray dogs
	y9c8mq29r1e:h  animals included in the present classification
	y9c8mq29r1e:i  animals that tremble as if they were mad
	y9c8mq29r1e:j  innumerable animals
	y9c8mq29r1e:k  animals drayd with a very fine camelhair brush
	y9c8mq29r1e:l  other animals
	y9c8mq29r1e:m  animals that have just broken a flower vase
	y9c8mq29r1e:n  aninals that from a long way off look like flies

A knowledge base organized according to this system could be indexed by these classmarks. As the initial sequence y9c8mq29r1e: occurs in the majoirity or totality of cases, it can be shortened by upper-case letters, giving

	A  animals that belong to the Emperor
	B  embalmed animals
	C  animals that are trained
	D  suckling pigs

In cases where the studied phenomenon is more relevant than the viewpoint, notation can be reversed to give priority to the phenomenon:

	mq98y(9c29r1e)  animals according to popular knowledge in China in the Middle Age

The sequence 98y, meaning "being topic of knowledge", can be substituted by the common facet 06:

	mq06(9c29r1e)  animals according to popular knowledge in China in the Middle Age

A similar device can be used also to express the method of study (y3) in Szostak's favoured sequence of phenomenon, theory, and method:

	mq03b  	 animals studied through observation
	mq04y03b animals according to theory Y studied through observation

and for Vickery's activities:

	mp07sh	plants studied for health applications		
	mp07vq	plants studied for cuisine applications


One particular viewpoint which is often adopted is that of academic disciplines studying phenomena. Although ILC classes represent phenomena instead of disciplines, the latter can be represented as a kind of phenomena, at the integrative level of knowledge:

	y  knowledge
	y8 	of object
	ys 		sciences
	ysd 			physics
	ysf 			chemistry
	ysh 			geology
	ysl 			biology
	ysl8nyr 			biology of forests
	ysq 			linguistics
	ysr 			sociology
	ysu 			economics
	ysu8nyr 			economics of forests

If now we set ys as the favoured class A, we obtain a discipline-based scheme similar to those of traditional bibliographic classifications:

	Ad 	physics
	Af 	chemistry
	Ah 	geology
	Al 	biology
	Al8nyr 		biology of forests
	Aq 	linguistics
	Ar 	sociology
	Au 	economics
	Au8nyr 		economics of forests


While works about literature, cinema, etc. must be classified in xl, xs etc., works of literature and cinema must not; indeed, they are not about arts, but are in form of art [Kyle 1959]. So, what are they about?

In most cases, literary works are about topics related with people and society, in a more or less fictional set. Thus, they can be classified as pY08f "fictional personalities", or s08f "fictional communities", etc., depending on what level is the focus one. 08f will not apply to e.g. documentary films.

For example, Maigret novels mainly deal with murders t70d, and the emotions and personalities p of people involved in them, in 20th century t1j France tnUc; thus, they can be classified as tnUc70d68p1j08f. If author is relevant, it can be expressed: tnUc70d68p1j08i006simenon. If one wants to account for the document being a video adaptation of Simenon novels, the 00v carrier suffix can be added. Wim Wender's film "The American friend" deals with friendship p3ew by a fictional story set in Germany 0829b in form of moving images 00v; thus, it can be classified as p3ew08f0829b00v.

On the other hands, if the form is more relevant than the contents, like in a collection of poems on very disparate subjects, the classmark can consist only of formal facets: 009h003UF "poems in French". The same can be true for abstract paintings or symphonies (although such cases as Smetana's "Moldau" also have a phenomenic dimension: jswr2ei009a "rivers, in Elbe basin, in form of art work").


How ILC works — ISKO Italia <> : 2005.08.04 - 2016.11.24 -     [how.htm until 2011.07.19]