Who inspired Matthew Flinders to be an explorer?

The practical reason for Matthew Flinders's voyages was to chart the Australian coastline and fill in the gaps left by previous English and Dutch explorers. This was the task for which he was commissioned.

Personally, however, while Matthew Flinders was inspired by reports of Captain James Cook's voyages, it was after reading Daniel Defoe's "Robinson Crusoe" that he decided he wanted to be an explorer and sailor.