at Northeast Portland’s Straight Blast gym, a string concerto echoes from the stereo. The atmosphere feels like a well-behaved library, not a macho sweatbox. Even so, within martial arts Straight Blast is known for its full-contact training style: students are more likely to battle each other than execute karate’s traditional kicks into thin air.

This two-fisted approach lends gym founder Matt Thornton renown as a trainer, but he’s now gaining notoriety for a different combative pursuit: philosophy. In blog posts, videos, and interviews, Thornton propounds an arch-skeptic’s approach to both fighting and life. He takes issue with both rival schools of martial arts and anyone who pursues what might be called faith-based thinking. “Belief absent evidence is a vice,” says the imposing 6-foot-8 fighter. After establishing a pugnacious rep online, Thornton is at work on a book that could introduce his muscular personality—and reverance for scientific method and rigorous testing of any belief— to a wider audience. 

In the gym, Thornton holds a black belt in Brazilian jiu-jitsu, and adapts that style’s emphasis on sparring to disciplines like boxing, judo, and Thai kickboxing. He meanwhile rejects traditional noncontact exercises and martial-arts mysticism as having limited self-defense value. “Once you train my way, you can’t do other stuff anymore,” he says. “It would be like being a doctor, but also practicing witchcraft on the side.”

“Once you train my way, you can’t do other stuff anymore.”
—Matt Thornton   

After 20 years, Straight Blast enjoys global appeal: 15 affiliated gyms or training groups in the US and 10 abroad, in places like Seoul, Cape Town, and Dublin. Traditionalists, on the other hand, don’t care for Thornton’s criticism of “dead” martial arts. San Francisco–based instructor Gary Moro scoffed: “The only people practicing ‘reality based’ fighting skills are ... in the military.” 

Meanwhile, quotes from British philosopher and logician Bertrand Russell and astronomer Carl Sagan weave through the tattoos that crosshatch Thornton’s forearms. Peter Boghossian, a Portland State philosophy professor and Straight Blast student, hopes the fighter’s book-in-progress can strike a blow for rationality. “Thornton can make complex ideas clear to a wide audience,” Boghossian says.

In all, Thornton seems to apply the spirit of contact sports to intellectual argument. “To get good at jiu-jitsu, you have to lose thousands of times,” he says. “If you say, ‘I’m never going to tap out,’ you’re never going to be any good.”