
"Historical records show that there was no real concept of probability in Europe before the mid-seventeenth century, although the use of dice and other randomizing objects was commonplace. Ian Hacking here presents a philosophical critique of early ideas about probability, induction and statistical inference and the growth of this new family of ideas in the fifteenth, sixteenth and seventeenth centuries. The contemporary debates center around figures such as Pascal, Leibniz and Jacques Bernoulli."--Jacket.
The latter book has a Wikipedia page with some more info - was surprised to see Hacking not mentioned here since the featured article is partly based on his work: https://en.wikipedia.org/wiki/The_Taming_of_Chance
Ian Hacking has two books, he is a philosopher, accordingly they have a broader outlook: "The Taming of Chance" "The Emergence of Probability"
Stephen Stigler's "The History of Statistics" seems to be the most popular history of statistics.
It was finally in the correspondence of Pascal and Fermat in 1654 that a mathematics for probability started to emerge. With the emergence of the laws of large numbers, this mathematics could be linked to observable real-world occurrence rates. (Ian Hacking's book "The Emergence of Probability" is a standard reference, http://www.jstor.org/stable/2184357?seq=1#page_scan_tab_cont...)
Suppose you were confronted with a stream of random numbers, and no intellectual or mathematical framework for quantifying them. Just coming up with a notion of a frequency curve (i.e., a density), and statistical independence of "unlinked" events would be a huge leap.
I used to TA an undergrad probability class, and in the first weeks, I'd ask the students to quantify some random variable, and they'd sometimes blankly look back and say, "it's just random" -- what we taught them is how you break that down in terms of the familiar quantities (densities, independence, correlations) and operations (multiplying for independence, integrating for expectation, integrating and renormalizing for conditioning).
So to get back to your original question, even a deterministic sequence, like
0, 1, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 0, 1, ...
could be regarded as random, and given a density and all the other folderol. And a "completely random" sequence of 0/1 equiprobable bits also has a density, etc. And so does everything in between.