Deliberate Abstraction

> Try mentally taking apart a car. Can you point to the component that supplies the transportation functionality?

Of course not. Transportation emerges from the interactions between air, fuel, cylinder, drive shaft, wheels, etc.

We can easily remove what does not contribute to Transportation.

Firstly, we take a shortcut: take the most economic car with the fewest features. That provides Transportation.

Then, start gutting things that obviously don't contribute to Transportation.

Let's assume that Transporation means getting from A to B in any weather, and any time of day or night. The roof is not removable even if the car is convertible because the roofless car doesn't function in any weather.

Thus, all fluff is gone. Power windows. Power steering. Remote door locks. Any sort of touchscreen nonsense. No stereo. Basic ventilation probably stays. Safety features like seatbelts should stay.

we are pretty much left with the chassis and cabin with doors and seats, belts and maybe air bags, steering wheel and pedals, speedometer and a few gauges, engine, transmission, wheels, brakes, suspension, headlights, turn signals, brake lights, and windshield wipers.

There are some tricky aspects. Suppose the car is internal combustion and we don't introduce an engine block heater. It then doesn't readily provide Transportation in areas where it is left parked outside overnight at seriously low temperatures below zero.There are geographically sensitive requirements under Transportation. Air conditioning is such. If the car is unbearably or even dangerously hot to be in, that interferes with its ability to provide Transportation.

> Try mentally taking apart a car. Can you point to the component that supplies the transportation functionality?

Transportation, in agile terms, isn't a feature or primary function – it's an epic. I agree with the conclusion that emergent behaviors cannot be well implemented solely as features, but it's also somewhat tautological, and the argument can only be constructed from the initial (invalid) premise.