Bradley M. Kühn of the Software Freedom Conservancy explores the philosophical question of when it is ethically acceptable for FOSS contributors to use proprietary software in creating or improving copylefted free software. Drawing on Kantian and Utilitarian frameworks, he argues that writing proprietary software is a far greater moral harm than using it, and that in certain circumstances using proprietary software becomes a moral imperative — particularly when doing so accelerates the delivery of software freedom to more users. He supports this with historical examples, including how early GNU contributors used existing proprietary Unix systems to build GNU tools faster, and with his own personal experience switching to a laptop with 77.5% proprietary firmware blobs to dramatically improve his productivity at SFC. His conclusion: pragmatic idealism means prioritizing users' software freedom over developers' purity, and reluctantly using proprietary software when it genuinely accelerates urgently needed FOSS advancement.
