[eesmith]

I think most of the points are invalid.

Amateur means something more like "doesn't get paid". Professional means "gets paid."

Consider amateur marathoners. Some indeed "stop when they achieve" their first marathon. Others dedicate years to participating in marathons, and running culture. But they are all amateurs.

Some amateur marathoners "have a goal" - do a marathon. Some "have a process."

Most amateurs runners do not "think they are good at everything".

Many amateur runners have coaches, and join running clubs, and read advice books, all to get feedback and coaching.

Go down the list, and pretty none of it applies to dedicated amateur marathon runners.

Nor does it apply to other fields, like dedicated amateur birdwatching.

[mongol]

I think the list is more relevant for how it describes professionals, and less relevant for how it applies to amateurs. From professionals we expect a certain level of efficiency and proficiency. From amateurs we generally don't but that does not mean there are no skilled amateurs in a field.

[atoav]

E.g. Sir Isaac Newton who was a professional mathematician but an amateur physicist.

Professionalism to me means a few things: - you earn money with the thing you do - given a outline of the project you can judge how long it will take - you also care about communicating your work - once you agree to do something, you do it unless you can’t