A big part of a dentist's income is yield from educational investment. The education and training is the capital.

By that measure nearly every job is white collar. Eg for any construction job you need to first get training and safe pass certification as well as purchase equipment such as good steel toe boots before you ever step foot in jobsite and start making money. What job do you not need to invest some amount of money into before you get your first paycheque?

If I were interpreting the statement charitably, I'd say there was a sliding spectrum of capital vs labour and most income sources sit between the two at varying positions.

In which case, yes, owning a plumbing business is closer to capital than working at one, which is in turn closer than doing unskilled manual labour on a job site. And on the other end, maybe owning an Airbnb which you clean yourself is closer to labour than owning a portfolio of ETFs.

> interpreting the statement charitably

Something I always intend to do and regularly find myself falling short of! Thank you, your interpretation makes sense (as most interpretations seeking nuance do)

The license to practice is another type of capital. Kind of like a taxi medallion but less transferable.

And a bricklayer's income is dependent on their investment in food they eat every day. Not a terribly useful distinction though.

Capex vs opex.

Could the dentist just stop working and continue to make that part of their income?