Agnosticism is the view or belief that the existence of God, of the divine or the supernatural is unknown or unknowable. Another definition provided is the view that "human reason is incapable of providing sufficient rational grounds to justify either the belief that God exists or the belief that God does not exist." The English biologist Thomas Henry Huxley coined the word agnostic in 1869, and said "It simply means that a man shall not say he knows or believes that which he has no scientific grounds for professing to know or believe." Earlier thinkers, however, had written works that promoted agnostic points of view, such as Sanjaya Belatthaputta, a 5th-century BCE Indian philosopher who expressed agnosticism about any afterlife; and Protagoras, a 5th-century BCE Greek philosopher who expressed agnosticism about the existence of "the gods". Defining agnosticism Being a scientist, above all else, Huxley presented agnosticism as a form of demarcation. A hypothesis with no supporting, objective, testable evidence is not an objective, scientific claim. As such, there would be no way to test said hypotheses, leaving the results inconclusive. His agnosticism was not compatible with forming a belief as to the truth, or falsehood, of the claim at hand. Karl Popper would also describe himself as an agnostic. According to philosopher William L. Rowe, in this strict sense, agnosticism is the view that human reason is incapable of providing sufficient rational grounds to justify either the belief that God exists or the belief that God does not exist. George H. Smith, while admitting that the narrow definition of atheist was the common usage definition of that word, and admitting that the broad definition of agnostic was the common usage definition of that word, promoted broadening the definition of atheist and narrowing the definition of agnostic. Smith rejects agnosticism as a third alternative to theism and atheism and promotes terms such as agnostic atheism (the view of those who do not hold a belief in the existence of any deity, but claim that the existence of a deity is unknown or inherently unknowable) and agnostic theism (the view of those who believe in the existence of a deity(s), but claim that the existence of a deity is unknown or inherently unknowable). Etymology Agnostic () was used by Thomas Henry Huxley in a speech at a meeting of the Metaphysical Society in 1869 to describe his philosophy, which rejects all