## Modern Logic

- Mod. Log.
- Volume 4, Number 4 (1994), 357-381.

### Wozu Algebra der Logik? Ernst Schröders Suche nach einer universalen Theorie der Verknüpfungen

#### Abstract

At the end of his life Ernst Schröder (1841-1902) regarded the formulation of a
general theory of operations as his "very own field of research." Already in his *Lehrbuch
der Arithmetik und Algebra* (1873) and especially in *Über die formalen Elemente der absoluten
Algebra* (1874) he had made the first steps towards establishing a "formal" or,
in its final stage, an "absolute algebra" proceeding from the assumption that there are
operations which allow to connect two objects of a given domain (not restricted to mathematical
objects) to a third, which belongs also to the domain. By this means Schröder
tried to go beyond the narrow boundaries of traditional arithmetic, and to embrace also
non-commutative numbers like quaternions. Through Robert Grassmann's *Formenlehre*
(1872), Schröder discovered the analogy between arithmetical and logical connectives, but
already late in 1874 he went further: he then treated formal logic and arithmetic as two
different models of formal algebra. His subsequent research was devoted to the analysis of
logic as such a model. Schröder considered his proof that the "second subsumption of the
distributive law" was not provable in the identical calculus without negation as one of the
main results of his *Vorlesungen über die Algebra der Logik* (vol. I, 1890). As a conclusion
from this proof, he distinguished between a "really logical calculus" (of groups, algorithms
etc.) without complete distributivity, and the identical calculus which had to contain a
special postulate to provide the problematic second subsumption. When Schröder studied
Peirce's algebra of relatives in the beginning 1890s, the focal point of his research returned
to his early program of an absolute algebra. The logic of relatives with its relative operations
following the laws of the absolute algebra seemed to provide the language for applying
the intended general theory of operations to all fields of mathematics and, beyond this, to
all fields of knowledge containing formal structures. In this modified conception Schröder
regarded arithmetic as part of a "general logic".

#### Article information

**Source**

Mod. Log., Volume 4, Number 4 (1994), 357-381.

**Dates**

First available in Project Euclid: 6 March 2008

**Permanent link to this document**

https://projecteuclid.org/euclid.rml/1204835351

**Mathematical Reviews number (MathSciNet)**

MR1301250

**Zentralblatt MATH identifier**

0812.01012

**Subjects**

Primary: 03-03: Historical (must also be assigned at least one classification number from Section 01)

Secondary: 01A55: 19th century 03G05: Boolean algebras [See also 06Exx] 03G10: Lattices and related structures [See also 06Bxx]

#### Citation

Peckhaus, Volker. Wozu Algebra der Logik? Ernst Schröders Suche nach einer universalen Theorie der Verknüpfungen. Mod. Log. 4 (1994), no. 4, 357--381. https://projecteuclid.org/euclid.rml/1204835351