“We men of study, whose heads are in our books, have need to be straightly looked after! We dream in our waking moments, and walk in our sleep.”

Source: The Dogs of Babel

Source: The Butterfly as Companion: Meditations on the First Three Chapters of the Chuang-Tzu
Context: How do I know that enjoying life is not a delusion? How do I know that in hating death we are not like people who got lost in early childhood and do not know the way home? Lady Li was the child of a border guard in Ai. When first captured by the state of Jin, she wept so much her clothes were soaked. But after she entered the palace, shared the king's bed, and dined on the finest meats, she regretted her tears. How do I know that the dead do not regret their previous longing for life? One who dreams of drinking wine may in the morning weep; one who dreams weeping may in the morning go out to hunt. During our dreams we do not know we are dreaming. We may even dream of interpreting a dream. Only on waking do we know it was a dream. Only after the great awakening will we realize that this is the great dream. And yet fools think they are awake, presuming to know that they are rulers or herdsmen. How dense! You and Confucius are both dreaming, and I who say you are a dream am also a dream. Such is my tale. It will probably be called preposterous, but after ten thousand generations there may be a great sage who will be able to explain it, a trivial interval equivalent to the passage from morning to night.

The statement "The future of all life, including our own, depends on our mindful steps." and much of the theme of this essay also occur later in his writings, including The World We Have : A Buddhist Approach to Peace and Ecology (2008), Ch. 1 : The Bells of Mindfulness, p. 3
The Sun My Heart (1996)
Context: All life is impermanent. We are all children of the Earth, and, at some time, she will take us back to herself again. We are continually arising from Mother Earth, being nurtured by her, and then returning to her. Like us, plants are born, live for a period of time, and then return to the Earth. When they decompose, they fertilize our gardens. Living vegetables and decomposing vegetables are part of the same reality. Without one, the other cannot be. After six months, compost becomes fresh vegetables again. Plants and the Earth rely on each other. Whether the Earth is fresh, beautiful, and green, or arid and parched depends on the plants.
It also depends on us. Our way of walking on the Earth has a great influence on animals and plants. We have killed so many animals and plants and destroyed their environments. Many are now extinct. In turn, our environment is now harming us. We are like sleepwalkers, not knowing what we are doing or where we are heading. Whether we can wake up or not depends on whether we can walk mindfully on our Mother Earth. The future of all life, including our own, depends on our mindful steps.

Attributed from posthumous publications

The Tragic Sense of Life (1913), X : Religion, the Mythology of the Beyond and the Apocatastasis

Source: Books, Spiritual Warrior, Volume I: Uncovering Spiritual Truths in Psychic Phenomena (Hari-Nama Press, 1996), Chapter 1: Dreams: A State of Reality, p. 18

1836
Notebooks, The American Notebooks (1835 - 1853)