επιστημοσύνη

05:24 Jul 12, 2019 

I can see your point. However, the definition of επιστημοσύνη includes knowledge, i.e. επιστημοσύνη η [epistimosíni] Ο30 (χωρίς πληθ.) : η ιδιότητα του επιστήμονα καθώς και το σύνολο των επιστημονικών γνώσεων που αυτός έχει.

05:22 Jul 12, 2019 

See my comments on the individual answers suggested. From the context, I understand this as being about an attitude or an approach to one's profession, rather than knowledge specifically. If there was a word in English, it would be "scientificness". As there is no such word, I suggest that the poster rephrase the sentence so as to use a phrase like "in a scientific manner", or "with a scientific approach".