I can understand that a predicate is a predicate because the truth or falsity of it depends on the specific value of the 'variable' or the 'part acting as a variable' in it. (specific value should be from the domain of course).
But let's have this predicate: 2 <= x <= 1 (Domain is all real numbers)
Now whatever value we substitute for x, the predicate results in a statement which is false and hence there is absolutely no doubt about its truth value. It is false independent of the value replaced.
Does this make this predicate a statement essentially?