Exploring the link between public engagement and logical soundness in Seoul’s spatial planning

Abstract

Long-term spatial planning is essential for sustainable cities, yet its logical consistency is rarely evaluated. This study investigates how public participation influences the logical soundness of plans by identifying 'non-sequitur fallacies' and assessing procedural integrity using the Sustainable Urban Mobility Plan (SUMP) framework. This paper compares South Korea's National Comprehensive Territorial Plan and the 2040 Seoul Plan. The findings reveal that while the National Plan maintained logical coherence through institutionalized, deliberative participation, the 2040 Seoul Plan exhibited significant logical gaps. This paradox stems from 'technical exclusion' during Steps 3-4 and 6-7 of the SUMP process, demonstrating that the quality and timing of participation are decisive. Finally, this study proposes a three-stage framework to integrate procedural rigour with substantive logic, offering practical recommendations for planning authorities to move beyond symbolic consultation toward a democratically consistent and accountable paradigm.