Why lighthouses?

My first thought this morning, 

On seeing this lighthouse, 

Was to mourn the days 

When we built things like this 

To protect one another; 

To make the stranger’s journey safer. 

But upon further reflection I wondered

If lighthouses were simply designed 

To protect investments. 

But my inner optimist won, and decided 

They were built out of the perception (Now lost?) 

That what benefits one benefits us all; 

Out of empathy for both 

 The sailor and the merchant and their families; 

The absolute conviction 

That what hurts one leaves all of us

Aching for their loss.