Kerik does not own a densitometer, and he makes wonderful prints. Don't get something like that just because a propellerhead like me starts talking numbers. The only reason I throw those numbers around is because of a sick fascination with the quantitative that dates back to childhood. They just provide a quantitative shorthand do describe something that your eyes and the meat computer in your head is just about as good at recognizing.
As far as infinite range of tones being a definition of tonal range, no, my point is that any analog process or any paper can give you an infinite range of tones. I think when most people use the phrase tonal range, they mean 'the difference between black and white' . But again, it is an imprecise term, and is being used when there are some accepted unambiguous terms around that describe what I think people are attempting to describe. Density Range [the transmission density difference between the shadow and highlight on a negative), Exposure Scale( the difference in LogD exposure required to make a print from pure white to pure black) are two such terms. They have precise meanings. Tonal range has about as much precision as me telling my spouse that her dress looks 'nice'. BTW, i learned long ago that line is not recommended.
Anyway, what I'm saying is don't get balled up in all the arcana here. Find what you like in a print and learn how to get what you like. The number stuff may help you if you are so inclined, but if you're not, just practice, practice, practice.