When new technologies are introduced to safety systems, they may raise some new discussions and clarifications about established practices. IEC 61508 represents a general framework which may apply to all electrical/ electronic/programmable electronic (E/E/PE) novel technologies aiming for safety-critical applications. At the same time, it is important to handle issues of inconsistency between the new concepts and sector-specific standards and guidelines that give more specific requirements to how the technical solutions shall be realized. An important starting point can be to clarify the governing principles of safe design philosophies, beyond the detailed clauses, in order to guide the discussion when new technologies require new design philosophies (e.g. on how to achieve the fail-safe function). When technical solutions are novel, it is also important to acknowledge the importance of a safe design process for building confidence to the solution. So, it can be of interest to discuss the role of the safe design process to reduce uncertainty associated with the performance of the new technical solution (e.g. battery instead of spring). This paper is intended to contribute to the foundation theory for safe design of novel subsea technology in the Safety 4.0 project, a research-based joint industry project which aims to develop a safety demonstration framework for the novel subsea technology.