Differential Propositional Calculus • 3
•
https://inquiryintoinquiry.com/2024/12/01/differential-propositional-calcul…
Casual Introduction (cont.)
Figure 3 returns to the situation in Figure 1, but this time
interpolates a new quality specifically tailored to account
for the relation between Figure 1 and Figure 2.
Figure 3. Back, To The Future
•
https://inquiryintoinquiry.files.wordpress.com/2023/11/differential-proposi…
The new quality, dq, is called a “differential quality”
by virtue of the fact its absence or presence qualifies
the absence or presence of change occurring in another
quality. As with any quality, it is represented in the
venn diagram by means of a “circle” distinguishing two
halves of the universe of discourse, in this case, the
portions of X outside and inside the region dQ.
Figure 1 represents a universe of discourse X together with a basis
of discussion {q} for expressing propositions about the contents of
that universe. Once the quality q is given a name, say, the symbol
“q”, we have the basis for a formal language specifically cut out
for discussing X in terms of q. That language is more formally
known as the “propositional calculus” with alphabet {“q”}.
In the context marked by X and {q} there are just four distinct
pieces of information which can be expressed in the corresponding
propositional calculus, namely, the constant proposition False,
the negative proposition ¬q, the positive proposition q, and
the constant proposition True.
For example, referring to the points in Figure 1, the constant
proposition False holds of no points, the negative proposition ¬q
holds of a and d, the positive proposition q holds of b and c, and
the constant proposition True holds of all points in the sample.
Figure 3 preserves the same universe of discourse and extends the basis of
discussion to a set of two qualities, {q, dq}. In corresponding fashion,
the initial propositional calculus is extended by means of the enlarged
alphabet, {“q”, “dq”}.
Resources —
Logic Syllabus
•
https://inquiryintoinquiry.com/logic-syllabus/
Survey of Differential Logic
•
https://inquiryintoinquiry.com/2024/02/25/survey-of-differential-logic-7
Regards,
Jon
cc:
https://www.academia.edu/community/lypQnm
cc:
https://www.researchgate.net/post/Differential_Propositional_Calculus