Logos is the core of the gameplay: it is the web of topics and arguments on which the conversation is played.
Topics are nodes, connected by links called Arguments. Here, characters in the game differ primarily by: which topics and arguments they know at the start of the conversation, and what are their opinions on various topics.
Topics, Biases and Arguments
Each topic is a node on which characters can have a positive, negative or neutral Opinion. This opinion can represent a judgement of
truth ("We should invade Bhutan": true or false),
subjective value ("Roses are beautiful": agree or disagree),
or relevance to the conversation ("Quine argues against Kant": we care or not really)
Arguments are links connecting an opinion on one topic to an opinion on another: if "Peace is better than war" is true, then "We should invade Bhutan" is false.
Any character's opinion is the product of the topics and arguments they know, and a few initial biases on certain key topics. Without these biases, everyone would have the same neutral opinion on everything.
The crucial idea here is limiting biases to a few topics, and making all other opinions the result of cascading logical links spreading out from these initial biases. This allows to change someone's opinion of almost anything, by identifying the roots of their belief and giving counter-arguments surgically where they have the most impact.
It also means that, provided you know someone's biases, you can generally guess their opinion on a new topic, which allows for strategic planning.
Link genres and fallacies
So far, we have assumed that all characters agree on arguments (link between two topics), and the only differences lie in their initial biases and knowledge of those links.
It seems that the web of arguments is absolute and static. But in real conversation, a lot of effort is devoted to contesting not the premises of an argument, but the argument itself. Some links may be erroneous: they could represent fallacious reasoning such as overgeneralization, ad hominem, and so on. We may even want the player and opponnents to be able to make up some fallacies on the spot, to convince their unsuspecting audience of something they do not believe themselves.
The problem of fallacious arguments is complex: we don't want people to be able to refute "real" logical links, but if we allow refuting only fallacious links, then it is obvious to the player which is which. Even if their character is fooled, the player will know exactly where to attack an opponent's argumentation.
The solution requires revising what we think of as logic: logical rules are not self-evident, they are learned. You cannot use the rules of logic to prove themselves, they are not a justifiable knowledge. They are simply a cognitive know-how - for instance, you learn an example of syllogism, and practice rearranging other arguments to fit this form, until the rule is so ingrained that you believe them to be true because logical [H.M. Collins Changing Order (1985), see also McFarlane]. Therefore, there is no such thing as absolutely true logical links just awaiting to be discovered: the web will be different depending on the reasoning rules that you have learned.
In gameplay terms:
- Arguments have genres: Syllogism, Analogy, Excluded middle, Bayesian inference...
- These genres are learned, most characters know most of them but no character knows them all.
- Links of a genre your character does not know are shown with "Unknown genre" and you can dispute them.
- Fallacious links made up on the spot have "Unknown genre" for everyone (including their creator!)
- Links successfully revealed to be fallacious cause their author to lose a huge amount of Face* (and trust from everyone present), but a successful defense under contestation causes the attacker to lose Face instead.
Therefore, if you see a link of an unknown genre, you can try to dispute them, but you are taking a risk: is it a fallacy, or simply a valid argument model that you do not know?
* See Ethos below.