I think calling philosophy "theory" is a bit of a reach. Theories (Relativity, Quantum, Evolution) draw on, and can be falsified by, direct evidence. Philosophy is more argumentation on subjects that won't have scientific basis (morality, meaning of life) or don't yet have one and may never (consciousness).
Also if you take the fully general meaning, it's so vague I don't understand how it's something you can 'love', but then maybe that's why I'm not a Philosopher.
Edit: The author's work https://en.wikipedia.org/wiki/Tim_Maudlin is all on the Theoretical Physics / Philosophy boarder, in which "theory" vs "experiment" is the more common usage.
I'd disagree that theory is something you can love since I strongly identify with this sentiment myself. I am not a practical man (as my wife is more than happy to vouch for), but I'm in love with ideas, concepts and abstractions. I love mulling them over and discussing them with like-minded people. It often doesn't matter much to me whether an idea has physical grounding or can be put into practice.
> I want to start off by emphasising that I am not proposing to take sides on the propositions expressed in this book. I’m an intellectual. Ideas are my trade. Show me an idea and i’ll taste it. Belgians are foodies; my much-loved colleague Andre Petry lives out in the country. Once when I was staying with him the field opposite his house delivered overnight a vast harvest of a kind of particularly delicious toadstool called coprina comatus, a delicacy regrettably of incontestably phallic appearance known to English country people as Old man’s tool. Most people I have met express shock and horror at being asked to eat it. Not so Andre. No Belgian will allow anything to get in the way of a new taste experience. It is the same with me and ideas.