Via Negativa – Omission/Removal/Avoidance of Harm

Taleb's risk-specific application of subtraction: in domains of uncertainty, avoiding harm is more reliable than pursuing benefit. You may not know what makes a good diet, but you know cigarettes are bad—so stopping smoking provides more certain health improvement than any supplement. In investing, avoiding catastrophic losses matters more than capturing gains. In medicine, 'first, do no harm' prioritizes omission over commission. The asymmetry: the downside of harmful practices is more certain and often larger than the upside of beneficial additions.

When to use it

When risk management is needed and the downside is more certain than the upside; when navigating uncertain environments where avoiding ruin matters more than optimizing returns; when building robust systems that need to survive before they can thrive; when simplifying complex decisions by focusing on what to avoid rather than what to pursue.

How it can help

Build your risk management around avoidance rather than optimization. Instead of asking 'what's the best investment?' ask 'what investments could ruin me, and how do I avoid them?' Instead of 'what's the best strategy?' ask 'what strategic mistakes would be fatal?' Inversion—working backward from catastrophe—is more reliable than working forward from optimization in complex systems. Create a 'never do' list: behaviors, exposures, and decisions with asymmetric downside that should be categorically avoided regardless of potential upside.