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  <front>
    <journal-meta>
      <journal-title-group>
        <journal-title>Cosmological and Astrobiological Review: Journal for the Study of the Universe, Life and the Natural Sciences</journal-title>
      </journal-title-group>
      <issn pub-type="ppub">3126-3836</issn>
      <issn pub-type="epub">3126-3844</issn>
      <publisher>
        <publisher-name>SAPCRAA</publisher-name>
        <publisher-loc>Banja Luka, Bosnia and Herzegovina</publisher-loc>
      </publisher>
    </journal-meta>
    <article-meta>
      <article-id pub-id-type="publisher-id">1582</article-id>
      <article-id pub-id-type="doi">10.65932/CAR-2026-1-3</article-id>
      <title-group>
        <article-title>The informational theory of biological individuality: howorganismal boundaries arise from information flow ratherthan physical membranes</article-title>
      </title-group>
      <contrib-group>
        <contrib contrib-type="author">
          <name>
            <surname>Larkin</surname>
            <given-names>Amanda</given-names>
          </name>
          <contrib-id contrib-id-type="orcid">https://orcid.org/0009-0002-7632-1444</contrib-id>
        </contrib>
      </contrib-group>
      <pub-date pub-type="epub">
        <day>29</day>
        <month>06</month>
        <year>2026</year>
      </pub-date>
      <volume>4</volume>
      <issue>1</issue>
      <fpage>50</fpage>
      <lpage>63</lpage>
      <self-uri xlink:href="https://sapcraa.com/article-preview/1582"/>
      <abstract>
        <p>Where does one organism end and its environment begin? The default answer in muchof biology is spatial: the boundary is the outermost membrane, the skin, the cell wall. This articleargues that the membrane is a poor guide to individuality and that the boundary of an organismis better located where information flow closes on itself. I develop the Informational IndividualityCriterion (IIC), a three-axis operationalization that scores any candidate system along informational closure (the contrast between internal predictive mutual information and boundary-crossing mutual information), integrated information (the irreducibility of the system&apos;s cause–effectstructure), and constraint-based autonomy (the organizational closure of the constraints thatmaintain the system). On this account, the organismal boundary is the closed surface that maximizes a composite individuality functional, not the surface drawn by lipids or cuticle. I test thecriterion on three cases that break the membrane intuition in opposite directions: the mammalianholobiont, in which many membranes enclose one informational individual; the multinucleatesyncytium, in which one membrane encloses several partly autonomous informational sub-individuals; and the colonial siphonophore, in which many zooid membranes are subordinate to asingle integrated colonial self. Across all three, the informational boundary systematically divergesfrom the physical membrane, and I quantify that gap with a Membrane–Information Divergencediagnostic. The upshot is that individuality is graded, sometimes nested, and frequently displacedfrom the membrane — an outcome that membrane-based criteria cannot represent but that aninformational criterion renders precise and, in principle, measurable.</p>
      </abstract>
      <kwd-group kwd-group-type="author">
        <kwd>biological individuality</kwd>
        <kwd>information flow</kwd>
        <kwd>integrated information</kwd>
        <kwd>causal closure</kwd>
        <kwd>autonomy</kwd>
        <kwd>holobiont</kwd>
        <kwd>syncytium</kwd>
        <kwd>colonial organisms</kwd>
      </kwd-group>
    </article-meta>
  </front>
</article>
