by Bernie Cohen
We see news today in Parliament and the Guardian that 20 leading academics have sent an open letter to MPs questioning whether the £6.2bn project to upgrade the UK’s National Health Service IT system will work. At the heart of this system of systems is the use of the electronic health record (EHR) and the ways in which it can be made available and shared. The approach is based on one of standardisation across the NHS as a whole, but the view of the academics being reported on is that the meaning of its content must frequently be contingent not only on who wrote it, but also on the context in which it is being read. The concern is therefore whether the fundamental premise on which the EHR is being built is flawed in some way. What underlies this concern?
Languages in general, and programming languages in particular, are formalised at a number of levels: lexical, which determines what sequences of symbols constitute valid terms in a language; syntactic, which determines what sequences of terms constitute valid statements; and semantic, which provides a mathematical domain and determines what object in that domain is denoted by each valid statement.
The only meaning that can be attributed to a statement in a language so formalised is the mathematical object that it denotes and the treatment of this kind of meaning, called denotational semantics (cf Strachey, Milne, Stoy, Schmidt etc.), is a large and complex mathematical field involving algebraic topology and category theory (cf the LNCS series on ‘Category Theory and Computer Science’).
Such statements may also be intended to have meaning in domains other than those of mathematics: in physics, sociology, anatomy, physiology, psychology, commerce, etc. In that case, the statements in the language comprise a model of some part of that domain and the intent is usually reflected in the names used to decorate statements: variables, procedures, types, classes etc. These names do not themselves guarantee that the statements provide a valid model of the domain. That is a matter of observation and experiment, which may be assisted by mathematics (in the entailment of consequences and the demonstration of inconsistency) but cannot be completed there.
This level of language description was first explored by the scholastics in the 14th century (cf the ‘Supposition Logic’ of Petrus Hispanus) but was neglected in the 17th and 18th centuries when the powerful methods of Newton, Leibniz, Laplace and Lagrange encouraged belief in a mechanical universe. It was revived in the 19th century by Charles Sanders Peirce who, independently of, and more extensively than Boole, formalised logic but also recognised the need for the other level of meaning, which he called ‘pragmatics’.
Pragmatics is concerned with value as experienced by the subject of a statement, an embodied individual (although the term was interpreted more widely than that by James et al). Peirce recognised that pragmatic considerations lead the individual to make distinctions in her world — ‘differences that make a difference’, as he put it — that are reflected in her statements. A collection of such distinctions he called an ‘ontology’. Since ontologies are essentially individual, it not being possible for there to be a ‘universal ontology’ (such as those proposed by Porphyry and Leibniz). Despite this, we succeed in communicating with each other as individuals because we all encounter the same objective reality, with which our separate ontologies must needs be consistent. Further, in many fields of human endeavour, such as medicine or engineering, a large community shares a common collection of distinctions, usually promulgated by an education system, which constitutes a locally universal ontology.
This is what archetypes are for. They record the locally universal ontology of a domain of discourse and provide that ontology with an abstract syntax and a denotational semantics.
A system of archetypes is therefore contingent on the state-of-the-art in its domain of discourse, and on the context of other domains’ locally universal ontologies, in which it is deployed.
[It is worth noting that the version of VistA developed in Seattle in the ’90s attempted to achieve something similar, but in reverse. It was front-ended with AI-based systems, called ‘cubes’, that were supposed to ‘project’ the data in patient records into the ontologies of specialist domains, both medical and administrative. Serious problems arose in the implementation of the cubes due to what was called ‘dirty data’, that is, fields whose recorded values did not satisfy the constraints demanded by the projection semantics. In retrospect, this was clearly an ontological problem.]
Thus, the archetypes of openEHR will, of pragmatic necessity, change with medical theory and practice and may have to be altered when composed, locally, with those of other domains with which the practice of medicine and the needs, acute and chronic, of the patient are involved, such as prosthetics, social services, hospital administration, psychotherapy, legislation, finance etc.
The composition of disparate, locally universal, ontologies was recognised by Peirce to be a deep and difficult theoretical problem, which he left as an open question. It is still unresolved. Since only the concerned individuals may negotiate a shared ontology, ontological composition cannot be completely automated. As yet, neither openEHR nor any other EHR system has anticipated this issue.
As we move into a technological era in which socially critical systems are built around large and complex, locally universal ontologies, such as openEHR, the Semantic Web, e-government and Network Centric Warfare, we will need increasingly powerful tools and methods to mediate pragmatic and ontological negotiations among embodied individuals. One such set of tools and methods, built around BRL’s PAN (Projective ANalysis), is currently being deployed within the context of its associated methods of asymmetric design.
Our goal is to be able to meet the challenge of managing the dynamic adaptability of large complex systems-of-systems to evolving and disparate contexts-of-use.