“The poets are in the vanguard of a changed conception of Being.”

Daniel Martin (1977)

Source: Farnham's Freehold (1964), Chapter 14 (p. 196)

§ 344
Agni Yoga (1929)

The Architecture of Theories (1891)
Context: Three conceptions are perpetually turning up at every point in every theory of logic, and in the most rounded systems they occur in connection with one another. They are conceptions so very broad and consequently indefinite that they are hard to seize and may be easily overlooked. I call them the conceptions of First, Second, Third. First is the conception of being or existing independent of anything else. Second is the conception of being relative to, the conception of reaction with, something else. Third is the conception of mediation, whereby a first and second are brought into relation.

Kropotkin here may be refering to the French scientist Joseph Fourier, and not the French social philosopher Charles Fourier
Anarchism: Its Philosophy and Ideal (1896)
Context: The whole aspect of the universe changes with this new conception. The idea of force governing the world, of pre-established law, preconceived harmony, disappears to make room for the harmony that Fourier had caught a glimpse of: the one which results from the disorderly and incoherent movements of numberless hosts of matter, each of which goes its own way and all of which hold each other in equilibrium.

Source: Systems Engineering Tools, (1965), p. 1

In science, this change has been manifested by a gradual transition from the traditional view, which insists that uncertainty is undesirable in science and should be avoided by all possible means, to an alternative view, which is tolerant of uncertainty and insists that science cannot avoid it. According to the traditional view, science should strive for certainty in all its manifestations (precision, specificity, sharpness, consistency, etc.); hence, uncertainty (imprecision, nonspecificity, vagueness, inconsistency,etc.) is regarded as unscientific. According to the alternative (or modem) view, uncertainty is considered essential to science; it is not only an unavoidable plague, but it has, in fact, a great utility.
Source: Fuzzy sets and fuzzy logic (1995), p. 1.

Preface.
The Turning Point (1982)