Boiling frog syndrome is a metaphor that refers to the creep of some insidious process that sinks in slowly and only becomes apparent over time. In it, a frog in increasingly hot water will not attempt escape as long as the temperature is increased gradually. It happens a little bit at a time, until the poor frog meets its end, in the end.

Scientifically, the fable is on poor footing — most frogs would actually leap to escape at some point along the way. But metaphorically, the analogy is a useful descriptor for some processes which tend empirically to have this quality of imperceptible changes over time resulting in seismic shifts when taken as a whole.

see also:

• slippery slope
• gradualism
• marginal changes
• evolution