If this claim was true, it would disallow science to make true claims, because no experiments can disprove such claims. Truth is a delicate matter and can't be handled by simple methods. Questions may not be settled, but they can be difficult to challenge.
Isn't that exactly how science work? It does not make true claims. It produces statements with disclaimers. If this and this then Y is true, as long as we don't observe Y.
You cannot use the scientific method to definitely say: "X is true".