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GDC 2002: Social Activities: Implementing Wittgenstein
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# GDC 2002: Social Activities: Implementing Wittgenstein

April 24, 2002 Page 1 of 3

This article starts with a theoretical case for what we call activity-orientated structure, arguing that activities are an important part of human life, and one that will become increasingly important in future simulations including human-like agents in believable contexts. Second, since there are so many different activities, it is important they can be added easily to the system and realized in the game world as actual (albeit non-physical) objects, rather than (say) abstractions in the minds of agents.

Implementational issues are also explored, focusing on the way activities should be added to the system. We argue that activities should be defined in a high-level language, which is compiled into C++. An example piece of activity-content, defined in this high-level language, is presented.

The Case for Activity-Orientated Structure

Why Social Activities are Important in the Simulation of Agents
Since this article is concerned almost exclusively with the notion of 'activities', it seems prudent to begin by trying to explain why we believe this concept merits such attention. In particular, we shall seek to establish successively that:

• Social activities are part of human life, and thus are usefully 'included' (in some sense) in simulations of human-like agents.
• Social activities are an important part of human life; thus their inclusion in simulations is correspondingly important to the believability of the simulation
• Social activities are the most important part of human life, that which distinguishes us from mere brutes. Thus, without addressing the activity concept in our simulations, we will be limited to simulating brutes.

Social activities are part of human life - agents who do not understand them can appear dumb. This minimal claim is most easily illustrated by considering a series of examples where an agent's lack of 'understanding' of activities and their relations can be cited as a failing of that agent.

• A chess computer. Although it is very good at chess, a chess computer is blind to the world around. It will never get bored of playing chess, and want to play something else. It does not understand, in other words, that playing chess is merely one activity amongst many, which satisfies some desires but not others. The chess computer doesn't understand the place of chess within the social flux - it doesn't understand that chess is a game played for recreation or competition.
• A problem with Black & White. In this game, a creature may be making friends with another, when he decides to interrupt this to go toilet. What is stupid about this behaviour is that the agent had no understanding of the consequences (for the activity of making friends) of stopping in mid-conversation to relieve himself. The same problem can arise in The Sims (a very entertaining piece of software): Peter's character was chatting up a lady, but then got tired, and in the middle of his chat he went off to have a bath. (The fact that this happens in both programs shows it is a moderately deep problem, and not a consequence of one particular implementation).
• Agents' understanding of Ownership. Nowadays, many games include agents owning objects. But this "ownership" is implemented in the simplest possible way. The following comments apply to SHRDLU, but apply directly to modern computer games. "SHRDLU cannot be said to understand the meaning of "own" in any but a sophistic sense. SHRDLU's test of whether something is owned is simply whether it is tagged "owned". There is no intensional test of ownership, hence SHRDLU knows what it owns, but doesn't understand what it is to own something. SHRDLU would understand what it meant to own a box if it could, say, test its ownership by recalling how it had gained possession of the box, or by checking its possession of a receipt in payment for it; could respond differently to requests to move a box it owned from requests to move one it didn't own; and, in general, could perform those tests and actions that are generally associated with the determination and exercise of ownership in our law and culture" [Herbert A Simon, "Artificial Intelligence Systems that Understand" (IJCAI-77, Proceedings) p.1064 [quoted in Dreyfus p.13] Agents (in current computer games) do not understand ownership because they do not understand the social activity in which ownership is embedded: ownership is a concept which belongs to the social activity of Enforcing Ownership, an activity which involves agents monitoring who owns what, and punishing others who mess with other people's things.

Social Activities add colour to our lives, lives which are otherwise coarse and materialist. From a certain perspective, our lives can seem empty. If all that there is in the world is other objects and agents, what is there for us to do except manipulate those objects and agents? All that we can want is to acquire as many objects as possible, and have as much influence over other people as possible.

This coarse and materialistic view of human nature is based on the assumption that all that exists is other objects and agents. Getting away from this dark picture involves admitting the existence of a variety of social activities. These activities elevate us because they give us new things to want. The lives of the Black and White creatures and the Sims characters are unquestionably materialistic because their desires are materialistic.

Maximally strong claim: participation in sophisticated social activities is the critical property which distinguishes people from animals. Heidegger distinguished between merely existing, as an animal exists, and full-fledged human existence. (Heidegger called this "Dasein" or "being-there", and characterised it as participation in the social flux of the world). This insight has filtered through into popular culture: a well-known mobile phone company has mooted that "life is made of one to ones". Even Swedish popsters Abba echo the sentiment - "Without a song or a dance what are we?" - in other words, it is our participation in forms of life that makes us uniquely human.

The sophisticated skills we prize about ourselves, our ability to reflect, communicate, care about others, are dependent on our ability to participate in various social activities. Social activities, rather than just being one of the many things the mind thinks about, are actually the things which make sophisticated thought possible. It is because we can participate in sophisticated social activities that we can have the sophisticated thoughts that we prize. Philosophers have given many examples of aspects of sophisticated personhood which are conditional on participating in social activities.

• Understanding of language. Wittgenstein's language-games are examples in which someone knows what something means because he understands the activity he is in. Investigations $2: "The language is meant to serve for communication between a builder A and an assistant B. A is building with building-stones: there are blocks, pillars, slabs and beams. B has to pass the stones, and that in the order in which A needs them. For this purpose they use a language consisting of the words "block", "pillar", "slab", "beam". A calls them out; -B brings the stone which he has learnt to bring at such-and-such a call. If someone understands what "pillar" means, he does so in virtue of understanding its role in the activity in which it is embedded. • Compassion towards others. Wittgenstein asks "Why can a dog feel fear but not remorse? Would it be right to say "Because he can't talk"?" [Zettel$518] The reason a dog can't feel remorse is that he cannot participate in the moral community in such a way as to recognise or manifest remorse. It is because he cannot participate in this activity that he cannot enter into these feelings.
• Feelings