There is a scientific explanation for everything. He's always believed that. Ghosts, Bigfoot, Loch Ness Monster, even that thing Gilligan swears is under the hammock at night, everything has a non-supernatural reason. Ghosts are the mind's way of coping with loss. Bigfoot is a fuzzy photograph of a bear. The noise under Gillian's hammock is Skipper. Nessie is an out of focus swan, although he's willing to concede some last remnant of the Jurassic period might have survived into the modern era. Science, after all, is about accepting facts even if those facts do not line up with previously-held beliefs.
When he tinkers together new machines out of scavenged parts from the ship and from the frankly weird array of items that wash up randomly along the beach, he uses the basic principles of engineering he learned in school and tried to teach to the hyperactive boys in his Scout troop. On the island, he has an even more distracted group to instruct, and no merit badges to hand out when they get it right.
"Like this?" Mary Ann asks him, as she finishes soldering the wires together. She's hardly a Boy Scout, but given his choice of other assistants, she's by far the ideal candidate. His technical explanations go over the heads of the other castaways or leave them cold: lack of interest, lack of patience, lack of curiosity, and in Gilligan's case, lack of ability not to set the hut on fire while operating a soldering iron.
"Just like that," he replies warmly.
"That was fun." Her smile is infectious, and for once, that word doesn't immediately make him begin thinking about pathogens or worry about the ramifications should one of them suddenly fall ill. Instead, he smiles back.
"Only twelve more wires to go, and we'll have a working phonograph." He glances at her. "A record player," he amends."
"I knew that, silly."
His smile doesn't go away and he's not sure what the explanation is for that. They have a few records with them, and he can't wait for the chance to play one as a test. When they're finished, and the hut fills with the sounds of the lives they've left behind them, maybe he'll work up the courage to ask her to dance.