Nope. Science always operates with a set of unknowns as its basis. Abiogenesis is an unknown. Creation out of nothing is an unknown. No human witness means, quite frankly, no certitude where the bigger picture is concerned. As donh pointed out, it took science over 80 pages to "prove" 1 + 1 = 2 and even then it took fifty years for a correction to manifest itself.
When science is taught it should be taught with qualifiers. It's not hard, and it is not harmful, to maintain a tone of uncertainty where the bigger questions are considered.
No individual can establsh a "legal" definition of science. There may be groups of scientists here or there that are in general agreement (for example we'd be hard pressed to find one that denies 1 + 1 = 2). But the reality is that every observer is his own scientist, and every obeserver operates with a large set of unproven assumptions.
Do you believe in a heliocentric solar system because you've seen with your own eyes, or because others have told you what they themselves have observed?
The textbook example you linked to had qualifiers.