It is the beginnings of science. We haven't seen any hints that he's done anything quantitative with those tools. Maybe given a lot longer he could get there. He hasn't got that much time, for now.
Quantifying helps you do science but its not needed. The cycle of science is sort of "observe->make prediction (a.k.a. hypothesis)->test prediction->analyze results loop"...
You can't get past the extreme basics without making some sort of statement that can be converted into something quantitative. Even Sociology leads to quantitative metrics, and hypotheses that can be tested in terms of them, in short order after setting up definitions.
Even basic stuff like Heliocentrism? Quantitative, based on thousands of individual measurements. Noticing that different weights fall at the same speed? Quantitatively backed, even if you don't need numbers to describe the result. Taxonomy of animals and plants? Okay, you can make some progress there before you hit a quantitative roadblock.
The tools Isaac has made are suited to observation, but they don't help on measuring and recording. So unless reality is very conveniently arranged so there's a lot of taxonomy to do, and it's the sort not requiring measurements, he's not going to get very far.