“I'm fairly certain. I could be some ghastly hallucination, a figment of my own imagination”

As "Chrissy"
The Search for Signs of Intelligent Life in the Universe (1985)

Source: Dark Whispers

Source: 1970s, Toward a General Social Science, 1974, p. 29

Source: Hons and Rebels

letter 206, c. 1787; in Goya, A life in Letters, edited and introduced by Sarah Simmons; transl. Philip Troutman, London, Pimlico, 2004
Goya understands that the social role he has reached (he is royal painter from 1789) will prevent him from attending places where people sing http://letteraturaartistica.blogspot.nl/2015/09/goya-life-in-letters-edited-and.html
1780s

The Other World (1657)
Context: I established myself in a fairly remote country house and entertained my imagination with various means of transport. Here is how I betook myself to heaven.
I attached to myself a number of bottles of dew, and the heat of the sun, which attracted it, drew me so high that I finally emerged above the highest clouds. But the sun's attraction of the dew drew me upwards so rapidly that instead of approaching the Moon, as I intended, I seemed to be farther from it than when I started. I broke open some of the bottles and felt my weight overcome the attraction and bring me back towards the earth.

Ron English's Fauxlosophy (2016)

Source: The Lover's Dictionary