Taleb is saying that the surgeon being a surgeon itself is the measure of his quality in the same manner that Lindy prescribes that age is a marker for stability.

The fact that he continues to be a surgeon provides you with information about his fitness as a surgeon. In the face of poor appearance, his existence as a surgeon provides you information about his quality.

Here's my best effort at explaining:

The Lindy effect describes cases in which real-life outcomes get better as one progresses down the "bad odds axis". For example, a 95-year-old selected at random from the general population might have a higher likelihood of being alive one year from now than an 80-year-old selected at random -- e.g., due to fact that living 95-year-olds tend to be people with good genetics who make healthy life decisions [0].

Taleb is somewhat sloppily trying to tie this phenomenon to the broad assertion that the relative aptitude of two given individuals at any given pursuit is often counterintuitive to first impressions. This ties into Taleb's favorite argument, which he predictably makes in a slightly different way with each new book or essay: what is often rewarded by society / companies / etc is the appearance of being good at something, rather than actually being good at it, and the pursuit of being perceived as good at something is not only not helpful to being better at it, but often actively counterproductive to said task....but if you ignore people's perceptions about what it means to be excellent, and "put skin in the game" by focusing on being excellent rather than cultivating that perception, you will be less susceptible to unforeseen bad events ("black swans").

[0] This very well may not be statistically true, just trying to put forth an illustrative example.