“In complexity economics one is not searching out the truth; one is simply searching for a statistical fit that can be temporarily useful in our understanding of the economy.”

In Search of a Better World (1984)
Context: There are uncertain truths — even true statements that we may take to be false — but there are no uncertain certainties.
Since we can never know anything for sure, it is simply not worth searching for certainty; but it is well worth searching for truth; and we do this chiefly by searching for mistakes, so that we have to correct them.

Thought at Sunrise (2007)
Context: To search for truth should be the main goal in one's life. This is a very difficult task. Let us begin by asking what is truth? What is untruth? To make this decision itself is difficult. Once the decision has been made, it is even more difficult to understand the limitations possible even in truth: elements of doubt and illusion. The Ultimate Truth is still far away, even if we are anywhere near relative truth, it should be deemed a great achievement. Those who live by truth sometimes become so dogged in their pursuit that even their truth seems a lie. Without control over passions and practicing neutrality, purity and straightforwardness, do we have a right to seek the truth?

7 Absolute Honesty, p. 8.
The Everything and the Nothing (1963)
Context: Absolute honesty is essential in one's search for God (Truth). The subtleties of the Path are finer than a hair. The least hypocrisy becomes a wave that washes one off the Path.
It is your false self that keeps you away from your true Self by every trick it knows. In the guise of honesty this self even deceives itself. For instance your self claims, I love Baba. The fact is, if you really loved Baba you would not be your false self making the self-asserting statement!

Flowers for Algernon (1966)
Context: Don't misunderstand me," I said. "Intelligence is one of the greatest human gifts. But all too often a search for knowledge drives out the search for love. This is something else I've discovered for myself very recently. I present it to you as a hypothesis: Intelligence without the ability to give and receive affection leads to mental and moral breakdown, to neurosis, and possibly even psychosis. And I say that the mind absorbed in and involved in itself as a self-centered end, to the exclusion of human relationships, can only lead to violence and pain.

Lecture discussing esoteric Christian mysticism
Mysticism

Source: Money: Whence It Came, Where It Went (1975), Chapter I, Money, p. 5

Greater than Sky, Vaster than Space, (2018), Part I

Patrick L. McGuire, Her Strong Enchantments Failing (p. 94)
Short fiction, The Book of Poul Anderson (1975)