Consider the following list of operations, each to be carried out in an economical way that permits a living to be made by the operators at each stage.

Dig materials out of the ground.

Subject them to chemical, mechanical and physical processes.

Mix the materials in different ways.

Design structures that will perform given functions with a given degree of reliability over a given lifetime, withstanding the forces and environments that they will encounter.

Make them into parts with different shapes.

Combine the parts to form complete structures.

What are these finished structures?

Aircraft?

Bridges?

Buildings?

Computers?

Jewellery?

Oil paintings?

Pottery?

Sculptures?

Ships?

Stained glass windows?

Vehicles?

Watches?

What do we call the makers of these artefacts?  Although the products are all made by similar series of operations, we give different names to the makers, and we don’t consider all of them to be closely related.

So what distinguishes an engineer, a jeweller and a painter, apart from the things they design or make?