He was arguing with Paul Nightingale, a professor of strategy at Sussex University's Science Policy Research Unit, who was drawing an analogy to say why trade with EU countries is more important for Britain than larger, but more distant, countries like China.
Carswell thinks it's the sun, and he's really pretty convinced about it.
For the record: The moon causes (almost all of) the Earth's tides. High tides come when the moon is either overhead or on the far side of the Earth.
The sun does have an impact – when the sun and moon align, you get especially high, "spring" tides – but the moon is overwhelmingly more powerful. That's because the sun, although it's much, much larger, is also much further away.
At least, that's according to experts. But people in this country have had enough of experts, so really, who knows?
Tom Chivers is a science writer for BuzzFeed and is based in London.
Contact Tom Chivers at firstname.lastname@example.org.
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