Caveat: My Latin knowledge (no pun intented) is slim to none, but I want to learn... so here goes.
Here is the pertinent section in English on Perseus (Leonard translation):
Lucretius, De Rerum Natura, BOOK IV, line 469
Same section in Latin:
Lucretius, De Rerum Natura, Liber Quartus, line 469
Pertinent word for knowing here is sciri. That's the word that is used throughout this section.
Charlton T. Lewis, Charles Short, A Latin Dictionary, scĭo
"In gen., to know, in the widest signif. of the word; to understand; perceive; to have knowledge of or skill in any thing, etc."
Here's a nice discussion on Stack Exchange on the difference between scio vs novi (and other "to know" verbs):
This is quite a large question, to which a comprehensive answer is easily found in the more comprehensive dictionaries under Know, with copious examples. However, in direct answer, there certainly are meanings not shared between the two, which I will try to summarise, although it is worth pointing out that the differences in usage can be very slight.
Scio is the most general word, meaning that you have a certainty, or at least clearly perceive, some fact(s) or other. It is followed by the kinds of clause that you would expect: acc. + inf., de + abl., relative + subj., neuter pronoun, and so on. Its opposite nescio, (‘not to know’, ‘be unaware/ignorant of’ etc.) is used similarly. But scio (and nescio) can also have the sense of ‘know how to …’ (particularly where it refers to a skill) as in scio scribere, nescio aratro uti.
The simple idea behind ‘not to know’ is expressed by ignoro (this being possibly more definite than nescio, which can be qualified by, for example, a clause after quin). The opppsite of ignoro is nosco, meaning ‘am acquainted with’, which is more usually seen in the perfect tenses, still giving a present sense in English. To claim a personal acquaintance, say, you might appropriately introduce yourself with te novi, or me no(ve)ris.
With, I think, a shade of meaning rather more active than that of simply learning (for which disco/didici or certior fieri is appropriate), the verb for the sense of ‘getting to know’ or ‘finding out’ is cognosco, most often in the perfect tenses to imply the knowledge for which scio in the present might sometimes be used equally well. Comperio is different again, with the sense of ‘know for certain’ or ‘tried and tested by experience’; compertum habet = ‘he knows without doubt’.
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I would use novi (not scio) to mean to have met someone.
Notus is the participle of nosco and in a specific sense means acquaintance, friend (at least post-Classically, L&S only lists the plural noti in this sense). It seems to me that there is no parallel with scio for this meaning.
From the definitions, it seems that one can scire and noscere something, but only noscere someone.
I can find examples of novi+person, but none of scio+person without some deed by that person being the thing that is actually known.
As you can see, "knowing" is much more complicated than the English word would have us believe. The Romans split up the semantic field much finer when it came to knowledge it appears.
