“Aristotle’s view that philosophy begins with wonder, not as in our day with doubt, is a positive point of departure for philosophy. Indeed, the world will no doubt learn that it does not do to begin with the negative, and the reason for success up to the present is that philosophers have never quite surrendered to the negative and thus have never earnestly done what they have said. They merely flirt with doubt.”

Vol. V, par. 265
Collected Papers (1931-1958)

Source: Disrupt You! (2015), p. 39

Theaetetus, 155d
Plato, Theaetetus

155, The Dialogues of Plato, Volume 3, 1871, p. 377 http://books.google.com/books?id=4kQNAAAAIAAJ&pg=PA377
Theaetetus

The Path to Enlightenment (1994) ISBN 1559390328

Philosophy : the basics (Fifth Edition, 2013), Introduction

1840s, On the Concept of Irony with Continual Reference to Socrates (1841)

if he does depart from his state of wonder, he has ceased to philosophize.
Source: Leisure, the Basis of Culture (1948), The Philosophical Act, pp. 105–106