All 4 Uses of

positive
in
Moby Dick

I am, sir, if it should be positively indispensable to do so; not to be got rid of, that is; which I don't take to be the fact.
Chpt 16-18 *

positively = absolutely (used for emphasis)

But when a man's religion becomes really frantic; when it is a positive torment to him; and, in fine, makes this earth of ours an uncomfortable inn to lodge in; then I think it high time to take that individual aside and argue the point with him.
Chpt 16-18

positive = absolute (used for emphasis)

But as perhaps fifty of these whale-bone whales are harpooned for one cachalot, some philosophers of the forecastle have concluded that this positive havoc has already very seriously diminished their battalions.
Chpt 103-105

There was some apprehension, but no positive alarm, as yet.
Chpt 127-129

positive = certain

Definitions:

(1) (positive as in: I'm absolutely positive!)
certain (having no doubt; or used for emphasis)
(2) (positive as in: had a positive effect)
good or beneficial
(3) (positive as in: positive feedback from my boss)
approval or agreement
(4) (positive as in: a positive attitude)
optimistic (expecting or focusing on good things); or agreeable
(5) (positive as in: The test came back positive.)
found a condition or substance to be present
indicating the presence of something being tested for -- especially a disease, condition, or substance
(6) (positive as in: a positive number)
greater than zero (of a number)
(7) (meaning too rare to warrant focus)
meaning too rare to warrant focus:

See a comprehensive dictionary for less common meanings of positive including some in the fields of electricity, physics, chemistry, medicine, philosophy, and grammar. Note that most all senses of positive indicate that something is good or present.