“Our perceptions may be distorted by training and prejudice or merely because of the limitations of our sense organs, which, of course, perceive directly but a small fraction of the phenomena of the world. Even so straightforward a question as whether in the absence of friction a pound of lead falls faster than a gram of fluff was answered incorrectly by Aristotle and almost everyone else before the time of Galileo. Science is based on experiment, on a willingness to challenge old dogma, on an openness to see the universe as it really is. Accordingly, science sometimes requires courage—at the very least the courage to question the conventional wisdom.”

The Believer interview (2013)
Context: Yeah, our view of reality, the one we conventionally take, is one among many. It’s pretty much a fact that our entire universe is a mental construct. We don’t actually deal with reality directly. We simply compose a picture of reality from what’s going on in our retinas, in the timpani of our ears, and in our nerve endings. We perceive our own perception, and that perception is to us the entirety of the universe. I believe magic is, on one level, the willful attempt to alter those perceptions. Using your metaphor of an aperture, you would be widening that window or changing the angle consciously, and seeing what new vistas it affords you.

"Understanding and Imagination in the Light of Nature"
Variant: The world which we perceive is a tiny fraction of the world which we can perceive, which is a tiny fraction of the perceivable world...
Context: Because the fact is, what blinds us to the presence of alien intelligence is linguistic and cultural bias operating on ourselves. The world which we perceive is a tiny fraction of the world which we can perceive, which is a tiny fraction of the perceivable world, you see. We operate on a very narrow slice based on cultural conventions. So the important thing, if synergizing progress is the notion to be maximized (and I think it's the notion to be maximized), is to try and locate the blind spot in the culture — the place where the culture isn't looking, because it dare not — because if it were to look there, its previous values would dissolve, you see. For Western Civilization that place is the psychedelic experience as it emerges out of nature.

"The Golden Rule: A Proper Scale for Our Environmental Crisis", pp. 41–42
Eight Little Piggies (1993)

Interview by Iara Lee for the film Modulations http://www.furious.com/perfect/stockhauseninterview.html (August 1997)
Attributed

2013, Fifth State of the Union Address (February 2013)

Source: The Principles of Agriculture, 1844, Section I: The fundamental principles, p. 3.

Source: The Drunkard's Walk, Chapter 2, The Laws Of Truths And Half - Truths, p. 28

Source: By Art Koroma, from page 256 of Holy Axiom Truth Exposed... the Bible Is a Myth (2014) note: It appears President Barack Obama started this misattribution. I can find no reference to this quote on the Internet prior to his May 15, 2016 commencement address at Rutgers State University. https://obamawhitehouse.archives.gov/the-press-office/2016/05/15/remarks-president-commencement-address-rutgers-state-university-new

Vilem Flusser, Aspects and Prospects of Tsai's Work, Art International, March 1974