There is a surge in interest in the development of open-domain chatbots, driven by the recent advancements of large language models. The "openness" of the dialogue is expected to be maximized by providing minimal information to the users about the common ground they can expect, including the presumed joint activity. However, evidence suggests that the effect is the opposite. Asking users to "just chat about anything" results in a very narrow form of dialogue, which we refer to as the "open-domain paradox". In this position paper, we explain this paradox through the theory of common ground as the basis for human-like communication. Furthermore, we question the assumptions behind open-domain chatbots and identify paths forward for enabling common ground in human-computer dialogue.

翻译：随着大语言模型的最新进展，开放域聊天机器人的开发兴趣激增。通过向用户提供关于可预期的共同认知（包括预设的联合活动）的极少量信息，对话的"开放性"本应被最大化。然而，证据表明效果恰恰相反。要求用户"随便聊什么"反而导致非常狭窄的对话形式，我们将此称为"开放域悖论"。在本立场论文中，我们通过作为类人交流基础的共同认知理论来解释这一悖论。此外，我们质疑开放域聊天机器人背后的假设，并为人机对话中实现共同认知指明了前进方向。