Top ontology( ies ); why bother? ONTOBRAS-2013 Chris Partridge partridgec@borogroup.co.uk Abstract A small number of top ontologies have been developed over the last decade or two. They are now starting to be implemented in IT systems. This talk will argue that they have the potential to play a significant part in IT; and that exploiting this depends upon a better understanding of their scope and how they can be deployed. It will argue that their scope potentially extends across a significant proportion of the IT market and that this claim is best understood in the historical context of previous information revolutions. Hopefully this will facilitate a better understanding of why top ontologies can be useful and how they can be deployed. T opics What is a top ontology? What should a top ontology look like ? What should a top ontology contain ? How to assess a top ontology? Where can top ontologies be deployed ? Why use a top ontology? Why is our ontology vision opaque? 3 What is a top ontology? 4 An information framework perspective 5 Information is implemented as a stored representation. Representation Domain Information is typically about a domain Good practice in the development of information systems, is to separate concerns. (See e.g. OMG’s MDA divisions) style.visibility style.visibility style.visibility Separating the two concerns 6 What is in the domain? How do we represent it? The content developer perspective: Work out what is in the domain and then represent it. Direction of focus is domain-to-model. The ontology tool developer perspective: Work out how to build a model whose icons can represent things in the domain. Direction of focus is model-to-domain. Domain (represented) Model (representation) style.visibility ppt_x ppt_y style.visibility ppt_x ppt_y style.visibility ppt_x ppt_y style.visibility ppt_x ppt_y style.visibility ppt_x ppt_y style.visibility ppt_x ppt_y Leads to two ways of defining an ontology 7 Domain (represented) Model (representation) The ontology is the domain. An ontology is "the set of things whose existence is acknowledged by a particular theory or system of thought." (E. J. Lowe, The Oxford Companion to Philosophy) The limit case: The question ontology asks can be stated in three words “What is there ?” and the answer in one “everything”. Not only that, “everyone will accept this answer as true” though “there remains room for disagreement over cases.” ( Quine , On What There Is) The ontology is the model. An ontology is an explicit specification of a conceptualization . A body of formally represented knowledge is based on a conceptualization ( Genesereth & Nilsson, 1987 ) A conceptualization is an abstract, simplified view of the world that we wish to represent for some purpose. Every knowledge base, knowledge-based system, or knowledge-level agent is committed to some conceptualization, explicitly or implicitly . (Tom Gruber) style.visibility style.visibility style.visibility Domain focus: an example 8 style.visibility ppt_w ppt_h style.visibility ppt_w ppt_h Layering the domain 9 An ontology is often divided into layers and shown graphically as a pyramid, with the top ontology at the top. The pyramid shape is intended to reflect that the top ontology contains general items that are ‘used’ across the lower levels; across a range of domains. What should a top ontology look like? 10 An example: IDEAS 11 Another example: DODAF 2 – DM2 12 DODAF 2 data model, known as DM2 Has IDEAS as its foundation Yet another example: an early BORO top ontology 13 It is helpful if the top ontology is comprehensive, if it lists all the kinds of things that exist Technically, if it is comprehensive, it is known as a categorical ontology, as it categorises the types of things that exist. What should a top ontology contain? Ontological architecture 14 Ontological architecture The top ontology should set the ontological architecture As well as ontological categories, this will typically be a selection of ontological choices* that shape the architecture that can be framed as architectural principles and patterns. The larger the overall ontology; the more need for architectural principles and patterns, the more critical the top ontology’s choices become. * Some references for ontological choices : Partridge, C. (1996). Business Objects: Re - Engineering for re - use. Oxford, Butterworth Heinemann. Partridge, C. (2002). LADSEB-CNR - Technical report 06/02 - Note: A Couple of Meta-Ontological Choices for Ontological Architectures. Padova , LADSEB CNR, Italy Recap of (2002) paper above. Borgo , S., A. Gangemi , N. Guarino , C. Masolo , and A. Oltramari . (2002). “ WonderWeb Deliverable D15 Ontology RoadMap .” The WonderWeb Library of Foundational Ontologies and the DOLCE ontology. p. 11 - 4 ROADMAP OF MAJOR ONTOLOGICAL CHOICES Salim K. Semy , Mary K. Pulvermacher , Leo J. Obrst . (2004). Toward the Use of an Upper Ontology for U.S. Government and U.S. Military Domains: An Evaluation. DOCUMENT NUMBER MTR 04B0000063, MITRE TECHNICAL REPORT p. 3-10 Table 2. Ontological Choices Summary. 15 Top ontology choices A top ontology should provide a framework for dealing with these choices consistently The choices offer a good way to illustrate and test how a top ontology does this. 16 change Some major metaphysical choices Major metaphysical choices include: Perdurantism versus endurantism Presentism versus eternalism Absolute versus relative space, time and space-time Modally extended versus unextended individuals Materialism and non-materialism Extensionalism versus non- extensionalism – I – universals Extensionalism versus non- extensionalism – II – particulars Topology of time – branching or linear 17 style.visibility style.visibility style.visibility style.visibility style.visibility style.visibility style.visibility style.visibility style.visibility style.visibility Discussion of change is old Around 500 B.C . Heraclitus put forward one view: “Everything flows and nothing abides; everything gives way and nothing stays fixed. You cannot step twice into the same river, for other waters and yet others, go flowing on. Time is a child, moving counters in a game; the royal power is a child's.” transience is basic, the present is primary. A generation or so later Parmenides put forward the opposing view: “There remains, then, but one word by which to express the [true] road: Is. And on this road there are many signs that What Is has no beginning and never will be destroyed: it is whole, still, and without end. It neither was nor will be, it simply is—now, altogether, one, continuous …” permanence is basic. time is at best secondary, at worst illusory Translation (for both): Wheelwright , Philip. 1960. The Presocratics . Indianapolis. 18 style.visibility style.visibility style.visibility style.visibility style.visibility style.visibility style.visibility style.visibility style.visibility style.visibility style.visibility Enormous literature in philosophy Still an active research area: Adams, Robert M., “Time and Thisness ,” in French, Peter, Uehling , Theodore, and Wettstein , Howard (eds.), Midwest Studies in Philosophy 11, Studies in Essentialism (University of Minnesota Press, 1986), pp. 315-329. Bigelow, John, “ Presentism and Properties,” in Tomberlin , James (ed.), Philosophical Perspectives 10, Metaphysics (Blackwell, 1996), pp. 35-52. Alexander, H.G. (ed. and trans.), The Leibniz-Clarke Correspondence (Manchester University Press, 1956). Aristotle, De Interpretatione , in Aristotle, The Complete Works of Aristotle (Princeton University Press, 1984). Aristotle, Physics, in Aristotle, The Complete Works of Aristotle (Princeton University Press, 1984). Bourne, Craig, A Future for Presentism (Oxford University Press, 2006). Bradley, F.H., Appearance and Reality (Swan Sonnenschein , 1893; second edition, with an appendix, Swan Sonnenschein , 1897; ninth impression, corrected, Clarendon Press, 1930). Haslanger , Sally, “Endurance and Temporary Intrinsics ,” Analysis 49 (1989), pp. 119-125. Haslanger , Sally, “ Humean Supervenience and Enduring Things,” Australasian Journal of Philosophy 72 (1994), pp. 339-359. Haslanger , Sally, “Persistence, Change, and Explanation,” Philosophical Studies 56 (1989), pp. 1-28. Hawley, Katherine, How Things Persist (Oxford University Press, 2001). Heller, Mark, The Ontology of Physical Objects: Four Dimensional Hunks of Matter (Cambridge University Press, 1990). Hinchliff , Mark, “The Puzzle of Change,” in Tomberlin , James (ed.), Philosophical Perspectives 10, Metaphysics (Blackwell, 1996), pp. 119-136. Kant, Immanuel, The Critique of Pure Reason, translated by Norman Kemp Smith (Macmillan, 1963). Keller, Simon, and Nelson, Michael, “ Presentists Should Believe in Time-Travel,” Australasian Journal of Philosophy 79 (2001), pp. 333-345. Le Poidevin , Robin (ed.), Questions of Time and Tense (Oxford University Press, 1998). Le Poidevin , Robin, and McBeath , Murray (eds.), The Philosophy of Time (Oxford University Press, 1993). Lewis, David, On the Plurality of Worlds (Basil Blackwell, 1986). Markosian , Ned, “A Defense of Presentism ,” in Zimmerman, Dean (ed.), Oxford Studies in Metaphysics, Vol. 1 (Oxford University Press, 2003). Markosian , Ned, “How Fast Does Time Pass?,” Philosophy and Phenomenological Research 53(1993), pp. 829-844. Markosian , Ned, “The Open Past,” Philosophical Studies 79 (1995), pp. 95-105. Maudlin, Tim, The Metaphysics Within Physics (Oxford University Press, 2007). Maxwell, Nicholas, “Are Probabilism and Special Relativity Incompatible?,” Philosophy of Science 52 (1985), pp. 23-43. McCall, Storrs, A Model of the Universe (Clarendon Press, 1994). McTaggart J., The Unreality of Time. 1908. Mind 17.68: 457–474. Meiland , Jack W., “A Two-Dimensional Passage Model of Time for Time Travel,” Philosophical Studies 26 (1974), pp. 153-173. Mellor, D.H., Real Time II ( Routledge , 1998). Newton-Smith, W.H., The Structure of Time ( Routledge & Kegan Paul, 1980). Price, Huw, “A Neglected Route to Realism About Quantum Mechanics,” Mind 103 (1994), pp. 303-336. Price, Huw, Time's Arrow and Archimedes' Point: New Directions for the Physics of Time (Oxford University Press, 1996). Prior, Arthur N., “Changes in Events and Changes in Things,” in Prior, Arthur, Papers on Time and Tense (Oxford University Press, 1968), pp. 1-14. Prior, Arthur N., “The Notion of the Present,” Stadium Generale 23 (1970), pp. 245-248. Prior, Arthur N., Papers on Time and Tense (Oxford University Press, 1968). Prior, Arthur N., Past, Present, and Future (Oxford University Press, 1967). Prior, Arthur N., “Some Free Thinking About Time,” in Copeland, Jack, (ed.) Logic and Reality: Essays on the Legacy of Arthur Prior (Clarendon Press, 1996), pp. 47-51. Prior, Arthur N., “Thank Goodness That's Over,” in Prior, Arthur N., Papers in Logic and Ethics (Duckworth, 1976), pp. 78-84. Putnam, Hilary, “Time and Physical Geometry,” Journal of Philosophy 64 (1967), pp. 240-247. Quine, W.V.O., Word and Object (MIT Press, 1960). Rea, Michael C., “Temporal Parts Unmotivated,” The Philosophical Review 107 (1998), pp. 225-260. Savitt , Steven, “There's No Time Like the Present (in Minkowski Spacetime),” Philosophy of Science 67 (2000), supplementary volume, Proceedings of the 1998 Biennial Meetings of the Philosophy of Science Association, pp. 5563-5574. Savitt , Steven (ed.), Time's Arrows Today: Recent Physical and Philosophical Work on the Direction of Time (Cambridge University Press, 1995). Shoemaker, Sidney, “Time Without Change,” Journal of Philosophy 66 (1969), pp. 363-381. Sider, Ted, Four- Dimensionalism : An Ontology of Persistence and Time (Oxford University Press, 2001). Sider, Ted, “ Presentism and Ontological Commitment,” Journal of Philosophy 96 (1999), pp. 325-347. Sklar , Lawrence, Space, Time, and Spacetime (University of California Press, 1974). Smart, J.J.C., Philosophy and Scientific Realism ( Routledge & Kegan Paul, 1963). Smart, J.J.C., “The River of Time,” Mind 58 (1949), pp. 483-494 (reprinted in Flew, Antony (ed.), Essays in Conceptual Analysis (St. Martin's Press, 1966), pp. 213-227). Smart, J.J.C., “ Spatialising Time,” Mind 64 (1955), pp. 239-241. Smith, Quentin, Language and Time (Oxford University Press, 1993). Stein, Howard, “On Einstein- Minkowski Space-Time,” Journal of Philosophy 65 (1968), pp. 5-23. Stein, Howard, “A Note on Time and Relativity Theory,” Journal of Philosophy 67 (1970), pp. 289-294. Swinburne, Richard, “The Beginning of the Universe,” Proceedings of the Aristotelian Society, Supplementary Volume 50 (1966), pp. 125-138. Swinburne, Richard, Space and Time (Macmillan, 1968). Taylor, Richard, Metaphysics, 4th Edition (Prentice-Hall, 1992). Thomson, Judith Jarvis, “ Parthood and Identity Across Time,” Journal of Philosophy 80 (1983), pp. 201-220. Thorne, Kip S., Black Holes and Time Warps (Norton, 1994). Tooley , Time, Tense, and Causation (Oxford: Oxford University Press, 1997). Van Inwagen , Peter, An Essay on Free Will (Clarendon Press, 1983). Van Inwagen , Peter, “Four-Dimensional Objects,” Nous 24 (1990), pp. 245-255. Weingard , Robert, “Relativity and the Reality of Past and Future Events,” British Journal for the Philosophy of Science 23 (1972), pp. 119-121. Williams, Donald C., “The Myth of Passage,” Journal of Philosophy 48 (1951), pp. 457-472. Yourgrau , Palle , Gödel Meets Einstein: Time Travel in the Göodel Universe (Open Court, 1999). Zimmerman, Dean, “The A-theory of Time, the B-theory of Time, and 'Taking Tense Seriously',” Dialectica 59 (2005), pp. 401-457. Zimmerman, Dean, “Persistence and Presentism ,” Philosophical Papers 25 (1996), pp. 115-126. Zimmerman, Dean, “Temporary Intrinsics and Presentism ,” in van Inwagen , Peter, and Zimmerman, Dean (eds.), Metaphysics: The Big Questions (Blackwell, 1998), pp. 206-219. Zwart , P.J., About Time (North-Holland Publishing Co., 1976 ). 19 McTaggart J., The Unreality of Time. 1908. Mind 17.68: 457–474 . style.visibility Ground the choice in an example Situation Car There is a car. It has a tyre (A). Changing tyre When the car was built, a tyre (B) was ‘installed’ o n the car. At some point in time, this tyre (B) was taken off and a new tyre (C) installed. 20 What is the issue? Count the objects Car perspective #20 – car #25 – car’s tyre (A). Changing tyre perspective #21 – original tyre (B). #22 – replacement tyre (C). Obvious puzzle Seem to be more objects than you can see when you look at the car What is the connection between tyres (A), (B) and (C)? 21 A Ontological principles in play Can two things be in the same place at the same time? (Makes pointing difficult) The original tyre (B) and the car’s tyre (A) seem to be the same for a while. Principle: identity (and difference) at a time Choice: Nature of change over time. Can the same thing be different at different times? (Makes re-identification difficult) The car has different tyres - (B) and (C) - as parts at different times. Principle: identity (and difference) over time Choice: Nature of change over time. 22 BORO’s solution – time-extended objects 23 B C Car Tyre (A) style.visibility style.visibility style.visibility style.visibility Overlapping pattern is commonplace 24 Another example Top ontology The top ontology should provide a framework that gives a consistent treatment for the metaphysical choices Where the top ontology is used for a domain, this will ensure a consistent structure across the domain Where the top ontology is used for across a number of domains, this will ensure a consistent structure across these domains 25 How to assess a top ontology? 26 Basis for assessment We call these ‘types of sophistication’ Based upon the notion of what makes a good scientific theory – so have a pedigree Normally list six characteristics generality. The degree by which the scope of the types in the improved model can be increased without loss of information simplicity. The degree by which the model can be made less complex explanatory power. The ability of the improved model to give increased meaning fruitfulness. The degree to which the improved model can meet currently unspecified requirements or is easily extendable to do so objectivity. The ability of the model to provide a more objective (shared) understanding of the world : in particular, to index a thing to its mode of existence as opposed to its mode of representation and/or application precision. The ability of the improved model to give a more precise picture of the business object These types are closely inter-related 27 Where can top ontologies be deployed? 28 Where to introduce the top ontology 29 Domain Representation a t the domain modelling stage style.visibility Which market? A significant amount of ontology work focuses on the Semantic Web; often at the representation end of the information framework However, there is a much wider market for top ontologies The spend on Enterprise Software ($254bn) is orders of magnitude bigger than Semantic Web A small slice of Enterprise Software will be bigger than a very large slice of Semantic Web 30 www.gartner.com/it/page.jsp?id=1513614 Relevant trends in enterprise software Top ontologies strengths in semantic integration – harmonisation can play well in the enterprise software space. Two trends that illustrate the need for a top ontology: Islands of automation Shift from greenfield to brownfield 31 Bridging islands of automation 32 Creates a need for integration and interoperability A common top ontology makes semantic integration easier From greenfield to brownfield 33 Greenfield Brownfield A problem space needing the deployment of software applications where there are NO existing (legacy) software applications. These typically develop from scratch, on the basis of a "clean sheet of paper ". A problem space needing the deployment of new software applications where there are pre-existing (legacy) software applications. There may be an opportunity to harvest the investment in the pre-existing application systems. A classic example of an enterprise legacy application: SABRE (Semi-Automatic Business Research Environment), a computer reservation system initially developed by American Airlines in the late 1950s – going live in 1960. The development cost at that stage was $ 40 million ( about $350 million in 2000 dollars) http://en.wikipedia.org/wiki/Sabre_(computer_system) style.visibility ppt_x ppt_y style.visibility ppt_x ppt_y style.visibility ppt_x ppt_y style.visibility ppt_x ppt_y style.visibility ppt_x ppt_y style.visibility ppt_x ppt_y Supporting the application renewal approach? 34 Re-development Modernisation The re-development of a legacy system on a modern technology platform. It aims to avoid the out-of-date architecture inherent in the legacy application. The reengineering, conversion or porting of a legacy system to a modern technology platform. It aims to retain and extend the value of the legacy investment through migration to new platforms In a brownfield site, (at least) two possible approaches to renewing the system. Whichever approach is used, a top ontology has a semantic integration (harmonisation) role to play Modernisation using a top ontology 35 Top ontology facilitates the application modernisation Migrate a t the domain layer level: Use the top ontology as a framework for the migration In a sense, the modernisation involves semantic integration (harmonisation) at a point in time. Why use a top ontology? What difference would using one make? 36 Transparent vision One way of appreciating the benefit is to look at an ‘old’ problem: Transparent vision* *Modern discussion of the history: (E.g.) Goodwin, Charles (1996). Transparent Vision. Interaction and Grammar. E. Ochs, E. A. Schegloff and S. Thompson. p. 370-404. Edward Craig, The Mind of God and The Works of Man (1987 ) What is transparent vision? The basic idea: Natural human vision is – out of the box – capable of seeing things as they are (define: transparent = capable of transmitting light so that objects or images can be seen as if there were no intervening material.) Natural human vision is transparent in that there is no need to think about whether what we see exists - we just see what exists. ultimate WYSIWYG The issue here is not whether vision operates automatically – it plainly does – but whether natural vision is such that its results are a good guide to what exists In other words, can we just look and read off our ontology (the set of things that exist)? 38 The 18th Century arguments Arguments for transparent vision: The ‘Image of God’ Doctrine: Man is made in God’s image, and that although human beings are far less perfect than God, human minds and God’s mind are the same kinds of thing ‘The Insight Ideal’ is derived from the ‘Image of God’ Doctrine: God in his goodness endowed human beings with faculties that enable them, in principle, to gain knowledge of the world he created for them. It is totally taken for granted that ‘the universe was in principle intellectually transparent …’ (Craig 1987, 38) This was challenged by, for example, David Hume in ‘A Treatise of Human Nature’ (1740) 39 A 5 th Century BC version Plato’s Cave Found in the Greek philosopher Plato’s work ‘The Republic’ (514a-520a) where it is used to compare "... the effect of education and the lack of it on our nature .“ In the dialogue, Socrates describe a gathering of people who have lived chained to the wall of a cave all of their lives, facing a blank wall. The people watch shadows projected on the wall by things passing in front of a fire behind them, and begin to ascribe forms to these shadows. According to Socrates , the shadows are as close as the prisoners get to viewing reality. Socrates then explains how the philosopher is like a prisoner who is freed from the cave and comes to understand that the shadows on the wall do not make up reality at all, as he can perceive the true form of reality rather than the mere shadows seen by the prisoners. style.visibility style.visibility style.visibility style.visibility style.visibility style.visibility style.visibility The ‘Just Label It’ - methodology 41 Now... that should clear up a few things around here If transparent vision is true No need for a top ontology Everyone knows that if you put 10 data modellers to work on the model for a fixed domain, you will end up with 12 different models. And none of these will really be a model of the real world. Certainly the modellers will not agree which one is. How do we explain this? But in the IT world style.visibility style.visibility Explaining the situation So, the question is: When I look at a domain, is my vision (the process of seeing) transparent? If it is transparent then it does not get in the way of seeing the domain – I see the domain directly Why in some cases is it transparent and in others not? Look in the literature, we find the answer Transparent vision is constructed When we get used to it, it feels natural – but it is constructed Naïve view is that it is just natural (Larson is mocking this) Different visions for different purposes: E.g. Botanical transparent vision – it would look obvious to a trained botanist Has the ontological community/profession constructed a transparent ontological vision? 42 Developing transparent ontological vision Looks like transparent vision (perception) is constructed not natural A profession can develop a transparent vision – e.g. botanists may see the same botanical things Is the ‘professional ontologists ’ vision transparent? If we take the data modellers case seriously, then plainly not What does this mean for ontological domain modelling? We need to work out how to: Construct the transparent professional vision First stage, make the community realise that their vision is not transparent Note. In a sense, developing the ontology and developing transparent vision is the same exercise. 43 Why is our ontology vision opaque? Aligning the information structure with the information technology 44 One source of opaque vision The way we see things is a product of our history In part it is driven by the information technology we grew up with – and our ancestors grew up with Hence, we see things in a way that is influenced by pen and paper technology and this, in turn, influences the way we structure our information. When there is a shift to a new technology (e.g. computing), our information structures need to adapt to this. We need to learn to see the opportunities created by new technologies; to create information structures that take advantage of them. Top ontologies are a tool that can guide and facilitate that change. BORO Analysis Date Time Transaction Type Transaction Number Currency _ 1 Amount _ 1 Counterparty Currency _ 2 Amount _ 2 1 / 1 / 2007 13 : 55 : 0 SpotFX 20070101 - 1 GBP 1 , 0 , 0 CitiBank USD 2 , 0 , 0 Legacy System Table Shift in information structures 46 style.visibility ppt_w ppt_h style.visibility ppt_w ppt_h style.visibility ppt_w ppt_h Located At Pattern Instance Name Pattern Happens In Pattern Asset Exchange Pattern Located At Pattern Located At Pattern Instance Happens In Pattern Name Pattern Instance Asset Exchange Pattern Instances BORO Active Universal Business Patterns Client Active Business Patterns Client Instance Information Shift in information structures 47 style.visibility ppt_w ppt_h style.visibility ppt_w ppt_h style.visibility ppt_w ppt_h style.visibility ppt_w ppt_h style.visibility ppt_w ppt_h style.visibility ppt_w ppt_h Summary Summary Hopefully the answers to these questions are clearer: What is a top ontology? What should a top ontology look like? What should a top ontology contain? How to assess a top ontology? Where can top ontologies be deployed? Why use a top ontology? Why is our ontology vision opaque? 49 Questions? style.visibility