Your roommate asks you to taste the milk in the refrigerator to see if it is sour. What source of knowledge is he asking you to rely on

common knowledge.

Explanation:

We all know that milk tastes sour if it is bad. Hope this helps.

i feel as if they would both catch on before to long because they would see them to frequent

the language of nature was a manifestation from god as he said "let there be light" and there was light the world began to assume visible, comprehensible form.

what ever we know now think of the old vision of creation we can be sure that with out the speaking of word -without language- we would have no science today with its striking power to illuminate the world.