“There is not only a close analogy between the operations of the mind in general reasoning and its operations in the particular science of Algebra, but there is to a considerable extent an exact agreement in the laws by which the two classes of operations are conducted.”

Introduction, Section IV, Of Theory, p. 7.
Institutes of Moral Philosophy (1769)

Geometric Calculus (1895) as translated by Lloyd C. Kannenberg (2000) "The Operations of Deductive Logic'" Ch. 1 "Geometric Formations"

That these are the laws employed in the demonstration of the principal theorems in Algebra, a slight examination of the processes will easily shew ; but they are not confined to symbols of numbers ; they apply also to the symbol used to denote differentiation.
p. 237 http://books.google.com/books?id=8lQ7AQAAIAAJ&pg=PA237; Highlighted section cited in: George Boole " Mr Boole on a General Method in Analysis http://books.google.com/books?pg=PA225-IA15&id=aGwOAAAAIAAJ&hl," Philosophical Transactions, Vol. 134 (1844), p. 225; Other section (partly) cited in: James Gasser (2000) A Boole Anthology: Recent and Classical Studies in the Logic of George Boole,, p. 52
Examples of the processes of the differential and integral calculus, (1841)

Civil Law and the Sabbath sermon (3 December 1882)
Miscellany
Context: Any law that takes hold of a man’s daily life cannot prevail in a community, unless the vast majority of the community are actively in favor of it. The laws that are the most operative are the laws which protect life.

Subjectively speaking, the essence of philosophy is certitude; for the moderns, on the contrary, the essence of philosophy is doubt: the philosopher is supposed to reason without any premise (voraussetzungsloses Denken), as if this condition were not itself a preconceived idea; this is the classical contradiction of all relativism. Everything is doubted except for doubt. The solution to the problem of knowledge − if there is a problem − could not possibly be this intellectual suicide that is the promotion of doubt; on the contrary, it lies in having recourse to a source of certitude that transcends the mental mechanism, and this source − the only one there is − is the pure Intellect, or Intelligence as such.
[2005, The Transfiguration of Man, World Wisdom, 3, 978-0-94153219-8]
Miscellaneous, Philosophy

Luhmann (1991) “Wie lassen sich latente Strukturen beobachten?,” in Paul Watzlawick, Peter Krieg (eds.), Das Auge des Betrachters: Beiträge zum Konstruktivismus. Festschrift für Heinz von Foerster, Piper, München-Zürich, p. 71; cited in: Heinz von Foerster (1993) " For Niklas Luhmann: “How Recursive is Communication?” http://e1020.pbworks.com/f/fulltext-2.pdf". Translated by Richard Howe.

Book I, Chapter 2, p. 66
The Origin of Consciousness in the Breakdown of the Bicameral Mind (1976)

Book I, Chapter 2, p. 65-66
The Origin of Consciousness in the Breakdown of the Bicameral Mind (1976)

3rd Public Talk, Bangalore, India (13 January 1973)
1970s