The example of Arendt’s dismissal of scientific discourse from political discussion underscores a much deeper political problem: a lack of intelligibility.
Every language is intelligible to some people and not to others. This is obviously true in the case of major languages like English and Chinese. It is less obvious but still a problem with different dialects of a language. It becomes a source of conflict when there is a lack of intelligibility between the specialized languages of expertise or personal experience.
For many, mathematical formalism is unintelligible; it appears to be so for Arendt, and this disturbs her, as she locates politics in speech and wants there to be political controls on scientists. But how many scientists and mathematicians would find Arendt intelligible? She draws deeply on concepts from ancient Greek and Augustinian philosophy. Are these thoughts truly accessible? What about the intelligibility of the law, to non-lawyers? Or the intelligibility of spoken experiences of oppression to those who do not share such an experience?
To put it simply: people don’t always understand each other and this poses a problem for any political theory that locates justice in speech and consensus. Advocates of these speech-based politics are most often extraordinarily articulate and write persuasively about the need to curtail the power of any systems of control that they do not understand. They are unable to agree to a social contract that they cannot read.
But this persuasive speech is necessarily unable to account for the myriad mechanisms that are both conditions for the speech and unintelligible to the speaker. This includes the mechanisms of law and technology. There is a performative contradiction between these persuasive words and their conditions of dissemination, and this is reason to reject them.
Advocates of bureaucratic rule tend to be less eloquent, and those that create technological systems that replace bureaucratic functions even less so. Nevertheless each group is intelligible to itself and may have trouble understanding the other groups.
The temptation for any one segment of society to totalize its own understanding, dismissing other ways of experiencing and articulating reality as inessential or inferior, is so strong that it can be read in even great authors like Arendt. Ideological politics (as opposed to technocratic politics) is the conflict between groups expressing their interests as ideology.
The problem is that in order to function as it does at scale, modern society requires the cooperation of specialists. Its members are heterogeneous; this is the source of its flexibility and power. It is also the cause of ideological conflict between functional groups that should see themselves as part of a whole. Even if these members do see their interdependence in principle, their specialization makes them less intelligible. Articulation often involves different skills from action, and teaching to the uninitiated is another skill altogether. Meanwhile, the complexity of the social system expands as it integrates more diverse communities, reducing further the proportion understood by a single member.
There is still in some political discourse the ideal of deliberative consensus as the ground of normative or political legitimacy. Suppose, as seems likely, that this is impossible for the perfectly mundane and mechanistic reason that society is so complicated due to the demands of specialization that intelligibility among its constituents is never going to happen.