Domain Theory

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Domain Theory

• Roberto Poli

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DomainsDomainsDomains

• We need domain theory for the same reasons
  science is developed into different branches
  Reality is too complex to be understood at a
  stroke
• The only way we have found to develop our
  understanding of reality is to fragment it into
  separate parts (our domains) and to proceed by
  analyzing one part at a time
• The guiding idea
• Segment the whole of reality into classes of
  connected phenomena
• Phenomena occurring within each class are more
  homogeneous than are phenomena pertaining to
  other classes, so that the task of explaining
  their behavior should be more easily accomplished
  
• Domain theory cannot be limited to science,
  however
• Many domains are only remotely, if at all,
  connected to science (common sense, behavioral
  practices, aesthetic experiences, etc)

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Questions about Types of Domains

• Are there different types of domain?
• How many different types should be distinguished?
• What is their internal organization?
• How are the different types related to each
  other?
• Is there any methodology which helps to establish
  a domains boundaries?
• Domains
• Sharply defined domains with well-defined
  boundaries
• Blurred domains, depending on highly pragmatic
  decisions/interests
• Many domains present intermediate values between
  these two cases
• Underdeveloped state of the theory of domain

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Domain

• Types of domain
• Domain in the proper sense (e.g. biology)
• Sub-domain or facet frameworks (e.g. genetics)
• Cross-domain (e.g. medicine)
• Micro-domain (e.g. edible substances)
• I shall presented the first two types in some
  detail
• Main difference between domains in the proper
  sense (first case) and all the other cases. This
  explains why finding a criterion with which to
  distinguish proper domains from the other
  domain-types is mandatory

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The Framework
Levels of reality distinguish types of entities
(material, psychological, social entities)
A level of reality usually requires a vast array
of cate-gories. I would like to see whether
domains can be organized around some basic types
of entities
Wholes distinguish types of structures
(aggregate, system)
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A Proposal

• Domain1 Categorically closed, maximal partition
  of reality
• Categorically closed even if the domains
  entities may be existentially dependent on lower
  and/or adjacent entities, they nevertheless
  require a categorical framework different from
  the one used to understand the entities of the
  existentially supporting levels
• Organisms require chemical entities (molecules)
  which require physical entities (atoms) as their
  matter. However, the frameworks needed to
  understand biology, chemistry and physics are
  different
• Maximal partition of reality the domain
  includes all the entities that are selected by
  its categorical framework
• Whatever the merits of this proposal, it entails
  that not any partition whatsoever is a domain (in
  the proper sense)

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From Levels to Domains

• Hypothesis For any domain, some of its entities
  are more characterizing than others
• Biology (simplified)
• Biological entity (BE)
• Living entity (LE)
• Organism (OR)

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Biological Entity (BE)

• BEs delimit the field of biology
• BEs include biological items such as the nucleus
  of a cell, the membrane of a cell, its
  organelles, DNA, mRNA, and urine. None of these
  is a properly living entity they pertain to
  parts of a living entity or to their products or
  waste (urine)
• BEs also include non-biological items such as the
  nests made by birds and the pebbles eaten by
  chickens. Some nests are made of twigs and other
  matter others are f.i. deliberately made holes
  in the ground. Holes and pebbles are not
  biological entities in any proper sense of the
  term. They pertain, however, to the field of
  biology, because they are constructed by
  authentically biological entities (organisms) or
  are needed by them. We can consider them as
  entities with a primary physical nature and a
  secondary biological one

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Living entities (LE)

• LEs constitute a specific class of BEs. All LEs
  are systems, while not all BEs are. Furthermore,
  LEs are metabolic systems, i.e. LEs are entities
  that can survive if appropriate nutrients are
  provided. Cells, tissues and organs are cases in
  point.

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Organisms (OR)

• ORs are autopoietic LEs, i.e. LEs able to produce
  the BEs of which they are composed. Two main
  types of ORs should be distinguished unicellular
  and multicellular
• The distinction between unicellular and
  multicellular entities requires to articulated
  along the customary distinction between
  prokaryotes and eukaryotes. The former are
  unicellular entities whose genome is not enclosed
  within the cells nucleus, while the latter can
  be either unicellular or multicellular and are
  such that their genome is enclosed within the
  cells nucleus
• A cell which is a unicellular organism is a BE, a
  LE and an OR. A multicellular organism as a whole
  is a BE, a LE and an OR. However, the cells of
  multicellular organisms are living entities but
  they are not organisms (a liver cell is a living
  entity but not an organism)

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Caveat!

• If one subtracts LEs from the field of the
  biological BEs, what remains coincides with the
  field of organic chemistry. This shows the link
  between biology and its underlining level of
  reality
• However, there are differences. The subtraction
  of living entities modifies the situation in such
  a way that a number of questions become
  unanswerable. Even if urine is a purely chemical
  substance (well, a mixture of substances), how
  can one explains its presence without taking
  organisms and their metabolism into
  consideration?
• The questions asked from within organic chemistry
  and those asked from within biology are
  different. This shows that they are different
  domains. The reason for their difference lies in
  the entities grounding their specific levels of
  reality molecules for chemistry and cells for
  biology

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Facets

• The next step after establishing the core
  categories is to determine the dimensions of
  analysis of the domains entities. This is where
  facet analysis comes in
• With reference to the domain of biology, two
  series of facets follow
• The first series lists the characteristics from
  which an organism as an actually given
  object-type can be seen.
• The second series of facets lists all the other
  characteristics, those not focused on the
  organism as an actually given object-type

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Facets, first series

• The first series is centred on the governing
  concept of organism as an individual whole and
  lists the viewpoints from which organisms as an
  actually given object can be seen. One can then
  consider at least the following four cases
  Classification (Taxa), Structure, Function,
  Behavior
• Classification models biological taxonomies
• Structure applies part-whole analysis to cells
  and organisms, for both parts, organs and
  tissues. Traditionally this type of analysis is
  called cytology for cells and anatomy for
  multicellular organisms
• Function corresponds to what is traditionally
  called physiology and model the working of the
  part descriptively listed by the previous facet
  of the organism structure. In the case of the
  facet of functions, (serious) variations are
  usually called pathologies (to be further
  distinct between intra- and inter-systemic
  pathologies)
• Behavior deals with the organisms actions. It
  requires consideration of the organisms
  environment (ethology)

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Facets, second series

• The second series of facets list all the other
  viewpoints, those not focused on the organism as
  an actually given object
• Two main cases derive
• Facets focussed on the organism as a whole. These
  may include the growth, development and
  reproduction of organisms
• Analysis of the various parts of this whole, e.g.
  the genes governing the production of the organism

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Facets, again

• Objects pertaining to different domains may
  require different facets
• Establishing a universal list of facets will
  guide analysis and help in maintaining greater
  methodological coherence across domains

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Facetsfacetsfacets

• By comparing and integrating the ancient
  Aristotelian list of categories with the list
  produced by the Classification Research Group,
  one obtains a 16-entry list
• A 16-dimension analysis, however, is both
  difficult to manage and cumbersome from a
  cognitive point of view
• Grouping the 16 dimensions into some groups
  provides an environment easier to understand and
  manage, and helps in adding consistency controls

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The Table of Facets
Item Analysis Process Context Spacetime
Name Kind(hyperonym) Internal pr Context(related to) Space
Ambit(type of) Operation Time
Structure Patient
Property Function
Matter Outcome
By-product
Agent
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Comments
Item Analysis Process Context Spacetime
Name Kind Internal pr Context Space
Ambit Operation Time
Structure Patient
Property Function
Matter Outcome
By-product
Agent

• Unbalanced groups of categories
• Relevance of the group of processes
• Context underrepresented (may depend on not
  having discussed wholes)
• Entries of the groups analysis and process
  are mutually connected