Purpose: The reasons women give for why they delayed diagnosis of breast symptoms are numerous and striking. Yet none prove reliable as indicators of those likely to delay, and most at risk women overcome all barriers, deciding instead to seek immediate diagnosis. This study looked deeper at the reasoning of symptomatic women sustaining confidence in a decision to delay diagnosis of self-discovered breast symptoms to discover how they sustained confidence in delay even when they appraised their symptoms as possibly indicative of breast cancer. Methods: Using argument and heuristic analysis techniques, we examined the structure and soundness of the reasoning process in interviews with 28 community women, 15 of whom continued to delay diagnosis, and 13 who sought immediate diagnosis. Argument structure, logical soundness, and dependence on heuristic strategies, were compared by group. Results- Both groups of women provided arguments for seeking diagnosis and arguments for delay. Prompt diagnosis-seekers used vivid stories of other women with breast cancer to explain their diagnosis-seeking, while the delayers used similar stories to justify on-going decisions to delay. Diagnosis-seekers offered more arguments for doing so (mean:10.38 arguments) than for delay (4.38). Delayers offered fewer arguments for seeking diagnosis (mean: 4.40) and many more for delay (17.47). Delayers abandoned sound and usually compelling arguments to seek diagnosis, relying instead on false information, poorly reasoned arguments, and logically created dominance structures around decisions to delay. Their symptom appraisal process was on-going, their decisions to delay resilient but requiring of maintenance. Conclusions: Intervention studies aimed at decreasing patient delay should target this dominance structure by questioning reliance on mistaken claims of control over possibly advancing cancer, satisficing when scheduling diagnostic visits, simulating a benign diagnosis rather than the prevention of late-staged cancer, prioritizing fear control over protection of life and challenging mistaken analogies and the abandonment of sound arguments for seeking prompt diagnosis.