“Let us… take in our hands the staff of experience… To be blind and to think that one can do without this staff is the worst kind of blindness.”

This is declared to be "an old Kantian maxim" in General Systems Vol. 7-8 (1962)‎, p. 11, by the Society for the Advancement of General Systems Theory, but may simply be a paraphrase or summation of Kantian ideas.
Kant's treatment of the transcendental logic in the First Critique contains a portion, of which this quote may be an ambiguously worded paraphrase. Kant, claiming that both reason and the senses are essential to the formation of our understanding of the world, writes: "Without sensibility no object would be given to us, and without understanding none would be thought. Thoughts without content are empty, intuitions without concepts are blind (A51/B75)".
Disputed

Source: Thinking, Fast and Slow

Source: Quotes from Thorns in The desert, P. 10.

Cows and armed guards on a college campus. Where is the truth amid all this subterfuge? http://www.robert-fisk.com/articles204.htm, April 2, 2003 <br class="br">2003

As quoted by David Milner, &quot;Kenpachiro Satsuma Interview I&quot; http://www.davmil.org/www.kaijuconversations.com/satsum.htm, Kaiju Conversations (December 1993)

Unsourced in The Philosophy of Mark Twain: The Wit and Wisdom of a Literary Genius (2014) by David Graham
Disputed

Source: When Women Were Birds: Fifty-four Variations on Voice

The Gold at the Starbow’s End (p. 381)
Platinum Pohl (2005)