As we discussed on IRC, &quot;data race freedom&quot; is equivalent to guaranteeing memory safety, and so, in a kind-of pedantic way, data race freedom is the core guarantee. That said, the original comment would&#x27;ve been better phrased as &quot;one of Rust&#x27;s core guarantees&quot;.<p>Furthermore, I still think the best phrasing of the rules is for that guarantee: if a rule is removed one can usually construct fairly simple programs that have data races&#x2F;memory unsafety. Of course, it is definitely true that the arbitrary rules have other benefits, but if there was a simpler scheme that gave the core memory safety without the other things, I think Rust would&#x27;ve adopted it.