All 4 Uses

positive
in
Gulliver's Travels
(Edited)

This project could not be of any great expense to the public; and might in my poor opinion, be of much use for the despatch of business, in those countries where senates have any share in the legislative power; beget unanimity, shorten debates, open a few mouths which are now closed, and close many more which are now open; curb the petulancy of the young, and correct the positiveness of the old; rouse the stupid, and damp the pert.
Chpt 3

positiveness = the state of being absolutely sure of something
...and they showed, with great strength of reason, "that the royal throne could not be supported without corruption, because that positive, confident, restiff temper, which virtue infused into a man, was a perpetual clog to public business."
Chpt 3 *

positive = good or beneficial
He was an honest man, and a good sailor, but a little too positive in his own opinions, which was the cause of his destruction, as it has been with several others; for if he had followed my advice, he might have been safe at home with his family at this time, as well as myself.
Chpt 4

positive = certain
So that controversies, wranglings, disputes, and positiveness, in false or dubious propositions, are evils unknown among the Houyhnhnms.
Chpt 4 *

positiveness = the state of being absolutely sure of something

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)
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.