Most people know what apple pie is.

Only a fraction of people can actually bake an apple pie.

Only a fraction of those people can actually get themselves to bake apple pies on a regular basis (usually bakers).

Knowing what something is, is head knowledge. Knowing how to do something is hand knowledge. Knowing how to get yourself to do what you already know how to do is heart knowledge.

Some people are exceptional at head knowledge (those with high IQs). Others are exception at hand knowledge (many athletes, artists, or multi-skilled people).

I think that being exceptional at heart knowledge is what it means to have a good work ethic.

A good work ethic means, no matter what you do, you can do it consistently and with sufficiently quality, day-in and day-out. Which is neither a matter of information or of skill.

Like both head and hand, its a type of knowledge. Meaning it can grow over time, if you nurture it.