“I have not thought that it stood in need of an empty hypothesis, like those subjects which are occult and dubious… as, for example, with regard to things above us”

Remarks after the Solvay Conference (1927)
Context: I consider those developments in physics during the last decades which have shown how problematical such concepts as "objective" and "subjective" are, a great liberation of thought. The whole thing started with the theory of relativity. In the past, the statement that two events are simultaneous was considered an objective assertion, one that could be communicated quite simply and that was open to verification by any observer. Today we know that 'simultaneity' contains a subjective element, inasmuch as two events that appear simultaneous to an observer at rest are not necessarily simultaneous to an observer in motion. However, the relativistic description is also objective inasmuch as every observer can deduce by calculation what the other observer will perceive or has perceived. For all that, we have come a long way from the classical ideal of objective descriptions.
In quantum mechanics the departure from this ideal has been even more radical. We can still use the objectifying language of classical physics to make statements about observable facts. For instance, we can say that a photographic plate has been blackened, or that cloud droplets have formed. But we can say nothing about the atoms themselves. And what predictions we base on such findings depend on the way we pose our experimental question, and here the observer has freedom of choice. Naturally, it still makes no difference whether the observer is a man, an animal, or a piece of apparatus, but it is no longer possible to make predictions without reference to the observer or the means of observation. To that extent, every physical process may be said to have objective and subjective features. The objective world of nineteenth-century science was, as we know today, an ideal, limiting case, but not the whole reality. Admittedly, even in our future encounters with reality we shall have to distinguish between the objective and the subjective side, to make a division between the two. But the location of the separation may depend on the way things are looked at; to a certain extent it can be chosen at will. Hence I can quite understand why we cannot speak about the content of religion in an objectifying language. The fact that different religions try to express this content in quite distinct spiritual forms is no real objection. Perhaps we ought to look upon these different forms as complementary descriptions which, though they exclude one another, are needed to convey the rich possibilities flowing from man's relationship with the central order.

Source: Morning Star (2016), Ch. 1: Only the Dark

1920s, Review of The Meaning of Meaning (1926)

Google search of the second sentence, in quotes, yields a trio of 2019 books alone, most (there and in following) attributing it to Kepler—e.g., see Prof Basden's 2019 work, [Foundations and Practice of Research: Adventures with Dooyeweerd's Philosophy, The Complex Activity of Research [§10—4.1 Less-Obvious Pistic Functioning in Research], Advances in Research Methods, Abingdon-on-Thames, UK, Taylor & Francis-Routledge, 1st, 9781138720688, https://www.amazon.com/Foundations-Practice-Research-Adventures-Dooyeweerds/dp/1138720682, February 25, 2020] (page 222).
While most citations of Kepler have been traced back to a translation of an original work, this quotation appears broadly without any such sourcing (e.g., Basden). Where it is sourced, the sources are either spurious (e.g., to the "New World Encyclopedia", a Paragon House/Unification Church product https://www.nytimes.com/1984/04/02/arts/unification-church-is-starting-a-publishing-house.html, wherein it is likewise unsourced), or to such sources as Henry Morris' 1988 creationist work, [Men of Science, Men of God: Great Scientists Who Believed the Bible, Green Forest, AR, Master Books, 21st reprint, 9780890510803, https://www.amazon.com/Men-Science-God-Henry-Morris/dp/0890510806, February 25, 2020] (page 21f).
Until a scholarly source is found that ties these statements to an original text from Kepler, they formally must be considered unattributed to Kepler.
Disputed quotes

Source: The Living Thoughts Of Kierkegaard

Essays, On Authorship and Style

Source: Dead Until Dark

Source: The Analects, Chapter VI