Deliberative Democracy and [!]

The previous section introduced a model transformer for democratic deliberation in line with the the- ory of deliberative democracy. This section shows that that two important claims for the philosophical literature on deliberative democracy can be formalised in our framework. We start by showing that deliberation can induce preference change. Afterwards, we show that deliberation leads to a better understanding among the agents.

In a deliberation, people might change their preferences because they are confronted with new informa- tion and new perspectives.2 Precisely because, as Dryzek and List (2003: 1) point out, “deliberation involves discussion in which individuals are amenable to scrutinizing and changing their preferences in the light of persuasion”, deliberative democracy regards people’s preferences as dynamic. In our framework, preferences might change as a result of [!]. Firstly, [!] transforms the epistemic indistin- guishability relations, which reflects the fact that agents learn new information. As the beliefs of the agents are defined in terms of their plausibility and their hard information, their doxastic state changes as well. Secondly, [!] transforms the motivational states, which reflects the fact that agents are confronted with new perspectives. Recall that in our framework the preferences of an agent are determined by his epistemic doxastic state, his motivational state or perspective and the properties that hold of the alternatives. As [!] changes both the epistemic indistinguishability relations and the motivational states, our framework is able to model preference change due to new information and new perspectives, as the following example shows:

2

This claim is made by all deliberative democrats. See, for instance, Bohman (1998), Cohen (1989), Elster (1986), Habermas (1996) and Gutmann & Thompson (1996, 2002).

Example. Deliberating about the energy policy

Suppose three politicians are deliberating about which energy policy the government should fund: wind energy (w), nuclear energy (n) or shale gas (s). For simplicity, assume that only the following three properties play a role in the decision at hand:

• P1: sustainability

• P2: low energy price

• P3: short implementation time

Thus, P := {P1, P2, P3}. In the actual world w, exactly the following properties are true of the

alternatives:

• Wind energy: P1 and P3.

• Nuclear energy: P2.

• Shale gas: P2 and P3.

Suppose agent 1 is a representative of the green party. Sustainability is so important for him that this is his only motivationally salient property. Agent 2 is extremely worried about the upcoming energy shortage. Therefore, it is of the utmost importance to him that the alternative the government will fund has a short implementation time. Additionally, a low energy price is motivationally salient for him. The motivational state of agent 3 consists of all the properties that play a role in the decision at hand. Thus, we get the following motivational states in the actual world w:

• S1(w) ={P1}.

• S2(w) ={P2, P3}.

• S3(w) =P.

Suppose, furthermore, that the meta-level prefrences of the agents are as follows:

• Letw

1 be the linear order that is induced lexicographically by P1 w1 P3 w1 P2.

• Letw

2 be the linear order that is induced lexicographically by P3 w2 P1 w2 P2.

• Letw

3 be the linear order that is induced lexicographically by P2 w3 P1 w3 P3.

In addition, assume that agents 1 and 2 are well-informed. That is, they possess hard information about which properties hold of which alternatives. Agent 3 is correctly informed with respect to properties P2 and P3, but believes that both wind energy and nuclear energy are sustainable, for

he has mistakenly equated sustainability with low CO₂-emissions. Under these assumptions, the preferences of the agents before deliberation are as follows, where Pw_i and Iw_i denote strict preference and indifference respectively:3

• wPw₁sIw₁n.

• sPw₂wPw₂n.

• nPw₂sPw₂w.

Agent 1 prefers wind energy because it is the only sustainable option. As the other options are not sustainable, he is indifferent between them. Agent 2 prefers wind energy and shale gas to nuclear energy, because both have a low implementation time. Moreover, he prefers shale gas to wind energy because the former gives a low energy price. Notice that we have not taken sustainability into account, since this property does not belong to the motivational state of the agent. For agent 3, low energy prices have top priority. Therefore, wind energy is his least preferred option. He prefers nuclear energy over shale gas, because he (falsely) believes that nuclear energy is sustainable whereas shale gas is not.

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More formally, letx, y∈ X and letxRwiydenote the fact that agentiweakly prefers alternativextoyat worldw.

ThenxPw

Suppose that deliberation takes place and, thus, that the agents share their hard information and their perspectives. After deliberation, the motivational state of all the agents equals P, because the agents have to take each other’s perspectives into account. Furthermore, all the agents have correct information about which properties hold of which alternatives, because this was distributed knowledge. More specifically, agent 1 takes the implementation time and the energy price into account. He comes to prefer shale gas to nuclear energy, because of its short implementation time. Options with a short implementation time are interesting for him, because they can can function as a bridge between a non-sustainable present and a sustainable future. Agent 2 takes into account sustainability as a result of deliberation. Because he is worried about the energy shortage, he has become convinced that sustainable options are better than non-sustainable ones, because sustainable energy sources cannot be depleted. Thus, he prefers wind energy to shale gas. Lastly, agent 3 learns in the deliberation that nuclear energy is not sustainable, because sustainability is not just about low CO₂-emissions, but also about the safety of the workers and waste reduction. Now that he has the right information, he prefers shale gas to nuclear energy. In summary, the preferences after deliberation are as follows:

• wPw₁sPw₁n.

• wPw₂sPw₂n.

• sPw₂nPw₂w.

Notice that the preferences of all the agents have changed as a result of deliberation. The preferences of agents 1 and 2 have changed due to the confrontation with new perspectives, whereas the prefer- ences of agent 3 have changed because of new information.4

Proponents of deliberative democracy praise deliberation not only because it might induce preference change, but also because it causes participants to better understand one another. As Knight & Johnson (1994: 289) argue, successful deliberation induces “common understandings of what is at stake in a given political conflict”. In our formal framework, this is reflected by the fact that [!] leads to a common motivational state. For alli, j∈ N and all w∈W, it is the case that after deliberation S_i!(w) = S_j!(w) = S

i∈N Si(w). In other words, after deliberation an agent considers a property or

reason to be motivationally salient iff the other agents do as well. Thus, the perspective of the agents upon the issue at stake is the same. Furthermore, deliberative democrats often claim that each agent’s perspective should be taken seriously. The following proposition shows that this is reflected in our formal framework:

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For a complete formalisation of this example, letN ={1,2,3}be the set of agents,X={a, b, c}the set of alternatives and_P={P1, P2, P3}the set of properties. Let the preference of all the agents be defined as belief-based weak dominance. The preference formation modelM= (W,∼i,≤i, Si,i, r)i∈N corresponding to our example is defined as follows:

• W ={w, w0}andwis the actual world

• ∼1=∼2={(w, w),(w0, w0)}and∼3=W×W.

• ≤1=≤2={(w, w),(w0, w0)}and≤3={(w, w),(w0, w0),(w, w0)}.

• S1(w) =S1(w0) ={P1}, S2(w) =S2(w0) ={P2, P3}andS3(w) =S3(w0) =P.

• The meta-level preferences of the agent are defined as follows:

– Agent 1: Pw1 {P1, P3} 1w{P1, P2} w1 {P1} w1 {P2, P3} w1 {P3} w1 {P2} w1 ∅andw 0 1 =w1. – Agent 2: Pw2 {P1, P3} 2w{P2, P3} w2 {P3} w2 {P1, P2} w2 {P1} w2 {P2} w2 ∅andw 0 2 =w2. – Agent 3: Pw3 {P1, P2} 3w{P2, P3} w3 {P2} w3 {P1, P3} w3 {P1} w3 {P3} w3 ∅andw 0 3 =w3.

• The valuation function is defined as follows: – r(w, a) =r(w0, a) ={P1, P3}.

– r(w, b) ={P2}andr(w0, b) ={P1, P2}.

Proposition 5.5. |=SiP →[!] V j∈N

SjP.

Proof. Left to the reader.

This proposition says that if a certain property or reason is motivationally salient to one of the agents before deliberation, it is motivationally salient for all of them after deliberation. In other words, each agent’s perspective is taken seriously.

In conclusion, our framework reflects two important claims from deliberative democracy about the power of deliberative processes, namely (i) that deliberation might induce preference change and (ii) that it leads to a better understanding among the agents. Furthermore, the model transformer [!] for deliberation has been developed in close connection with the deliberative democratic literature. Therefore, we may conclude that the models for preference formation together with the dynamic operator [!] are a good mathematical presentation of democratic deliberation.