I don't see why this is true. Just because a thing is difficult to precisely define, doesn't mean it doesn't exist, nor does it mean you can't get closer to it.
I could say that I'm "taking strides towards becoming a better person" and that could still have meaning, despite the lack of any objective measure and, even, with the understanding that "a better person" could change over time.
I could say that I'm "taking strides towards becoming a better person" and that could still have meaning, despite the lack of any objective measure and, even, with the understanding that "a better person" could change over time.