This denotes a living "thing", one that can make a decision. A placard, say, is neither fallible nor infallible.
A better way of putting it. However, I am also pointing to the fact that English translations of the Bible are not what the authorized Greek versions are - they are approximate to them. That is why the Magisterium is required to teach the correct interpretation; otherwise Luther's every milkmaid will interpret any way and every way.