No, the point is that the sentence contradicts itself. It is a statement that implies no further progress can be made about its claim.
Science and the scientific method is basically the best means by which we can understand the physical world, but it doesn't help us determine the nature of truth, ethics, or the nature of science. It works on various assumptions (e.g. physical matter actually exists, it is possible to gain knowledge about physical matter, there is such a thing as time, logic is a valid aapproach to determining truth) that it cannot validate.