He had a certain disdain for tangible evidence, such as footprints and cigarette ash, and would maintain that, taken by themselves, they would never enable a detective to solve a problem.

他对脚印和香烟灰等有形证据有一定的蔑视， 并坚持认为， 仅凭这些证据， 侦探永远无法解决问题。