The personal digital twin extends to individual persons, a concept that originated in engineering to twin complex machines with a digital simulation containing a model of its functions to monitor its past and present behaviour, and repair, correct, improve or otherwise ensure its optimal operation. Several independent trends in technological developments are seen to converge towards the elaboration of the digital replication of individual human data and life history, notably in health industries. Among the main ones, we consider the ubiquitous distribution of digital assistants, the rapid progress of machine learning concurrent with the exponential growth of ‘personal’ Big Data and the incipient interest in developing lifelogs. The core hypothesis here is that among the psychological effects of the digital transformation, the externalization of cognitive faculties such as memory, planning and judgement, the decision-making processes located within the human person are also emigrating to digital functions, perhaps as a prelude to a later re-integration within the person via brain–computer interfaces. The paper concludes with ethical considerations about these ongoing developments.

This article is part of the theme issue ‘Towards symbiotic autonomous systems’.

个人数字孪生扩展到个人，这一概念起源于工程学，将复杂机器与数字模拟相结合，其中包含其功能模型，以监控其过去和现在的行为，并修复、纠正、改进或以其他方式确保其最佳运行。技术发展的几个独立趋势被视为趋向于详细说明个人人类数据和生活史的数字复制，特别是在健康行业。在主要因素中，我们考虑了数字助理无处不在的分布、机器学习的快速进步与“个人”大数据的指数增长以及对开发生活日志的初期兴趣。这里的核心假设是，在数字化转型的心理影响中，诸如记忆、计划和判断等认知能力的外化，位于人体内的决策过程也正在迁移到数字功能，这可能是后来通过脑机接口重新整合到人体内的前奏。本文最后对这些正在进行的发展进行了伦理考虑。

这篇文章是主题问题“走向共生自治系统”的一部分。