AI Transparency in Trustworthy AI : From Metaphor to Governance Tool in EU Technology Regulation

Transparency has emerged as a fundamental component of ethical AI guidelines around the world. In the European Union (EU), it is recognised as one of the core principles for fostering Trustworthy AI, and serves as a cornerstone in building an ecosystem of trust within the AI governance framework.However, to support these ambitious policy objectives, the concept of transparency must be translated into clearly defined and implementable measures. Thus, by employing a combination of legal-doctrinal and socio-legal approaches, this compilation thesis aims to contribute to a clarified understanding of the concept of AI transparency in the EU’s AI governance discourses. I examine the concept of AI transparency across four levels of abstraction: as a stand-alone objective, as a governance ideal, as a governance tool, and as a ‘floating signifier’. Focusing in particular on AI transparency as a governance ideal and as a governance tool in relation to the EU’s policymaking objective of Trustworthy AI, I analyse how AI transparency has been conceptualised, designed, and implemented for two stakeholder groups — individuals and oversight bodies — within the governance frameworks of the General Data Protection Regulation (GDPR), the Digital Services Act (DSA), and the Artificial Intelligence Act (AIA).The main argument advanced in the thesis is that while AI transparency directed at individuals (understood as data subjects, service recipients, and natural persons) remains relevant, it is the effectiveness of oversight-oriented AI transparency that is crucial to the enforcement of the EU technology regulation and is, ultimately, foundational in the EU’s pursuit of Trustworthy AI. Although transparency is central to the EU’s vision for Trustworthy AI, its effectiveness depends on how legal obligations are interpreted, implemented, and enforced in practice.