prize8-9, Exercise 1: "Lighthouses are obsolete"

Model answer (check the details), using the six questions:

1. Who says it? Commentators who point to satellite navigation, and sometimes budget-minded officials; lighthouse enthusiasts say the opposite.
2. What exactly is claimed? That lighthouses no longer serve a purpose. "Obsolete" could mean useless, or simply less needed than before.
3. What would count as evidence? The number of lights still maintained by the authorities, how many ships and boats use them, the rate of satellite failure or jamming, and the policies of the authorities and international bodies.
4. Compared with what? Their importance in 1850 or 1900, and with other aids such as GPS and radar.
5. Which period? Today, as against the 19th and early 20th century.
6. What would change my mind? Evidence that no vessel now relies on the lights, or that the authorities have stopped maintaining them for navigation.

Verdict: they are less essential than before, since most ships use satellite navigation, but they are not obsolete. They are used as a back-up, by small craft, as a mark of a danger and as part of a layered system (check). A careful sentence: "Lighthouses are no longer the main navigation aid for large ships, but they remain in service as a back-up and for small vessels."

Care: practices differ between countries and authorities. Check current policy for the area in question.