Verdict
It is not in Aristotle's work
It is found in no work of Aristotle. It appears attributed to him in American books from 1959 (Lowell L. Bennion, Religion and the Pursuit of Truth) and seems a distortion of Nicomachean Ethics I 3, 1094b23–25, which says that an educated person looks for as much precision in each subject as its nature admits.
What they did say
Verified words of Aristotle
«“All men by nature desire to know.”»
Metafísica I (A) 1, 980a21. Inglés: trad. de W. D. Ross (Oxford, 1908); español: trad. propia del griego.
«“For it is owing to their wonder that men both now begin and at first began to philosophize.”»
Metafísica I (A) 2, 982b12–13. Inglés: trad. de W. D. Ross (1908); español: trad. propia.
«“And indeed the question which was raised of old and is raised now and always, and is always the subject of doubt, viz. what being is, is just the question, what is substance?”»
Metafísica VII (Z) 1, 1028b2–4. Inglés: trad. de W. D. Ross (1908); español: trad. propia.
