Key ideas from a 25-year collaboration at technological forecasting & social change

• We recap key ideas from 25 years of Linstone–Phillips conversation.
• A deep view of systems and complexity must drive our responses to global problems.
• Ideas of discounting and multiple perspectives are updated and generalized.
• Sharpened definitions of innovation and technology assessment help focus decision making.
• We apply these ideas to comment on recent directions in big data and artificial intelligence.

Since their first meeting in 1991, the authors have enjoyed a friendly dialog centered around topics of interest to the journal Technological Forecasting & Social Change. Now, five years after Phillips succeeded Linstone as Editor-in-Chief of the journal, we recap the driving ideas that have characterized the partnership.The ideas span areas of systems, complexity, and scientific progress; the nature and measurement of innovation, social change, and technological change; the limits to growth; and multiple perspectives, as these pertain to technology forecasting and assessment. Collectively, the ideas and discussions have shaped our editorial philosophy and have appeared piecemeal in TFSC research papers, perspective pieces, and editorials. We now restate these key ideas in hopes of maximum clarity for researchers, managers, and policy makers.