Passing lambda as function pointer

Is it possible to pass a lambda function as a function pointer? If so, I must be doing something incorrectly because I am getting a compile error.

Consider the following example

typedef bool(*DecisionFn)();

class Decide
{
public:
    Decide(DecisionFn dec) : _dec{dec} {}
private:
    DecisionFn _dec;
};

int main()
{
    int x = 5;
    Decide greaterThanThree{ [x](){ return x > 3; } };
    return 0;
}

When I try to compile this, I get the following compilation error:

In function 'int main()': 17:31: error: the value of 'x' is not usable in a constant expression 16:9: note: 'int x' is not const 17:53: error: no matching function for call to 'Decide::Decide(<brace-enclosed initializer list>)' 17:53: note: candidates are: 9:5: note: Decide::Decide(DecisionFn) 9:5: note: no known conversion for argument 1 from 'main()::<lambda()>' to 'DecisionFn {aka bool (*)()}' 6:7: note: constexpr Decide::Decide(const Decide&) 6:7: note: no known conversion for argument 1 from 'main()::<lambda()>' to 'const Decide&' 6:7: note: constexpr Decide::Decide(Decide&&) 6:7: note: no known conversion for argument 1 from 'main()::<lambda()>' to 'Decide&&'

That's one heck of an error message to digest, but I think what I'm getting out of it is that the lambda cannot be treated as a constexpr so therefore I cannot pass it as a function pointer? I've tried making x const as well, but that doesn't seem to help.