- Leon Conrad’s presentation talks about “marked” and “unmarked” states.
He uses checkboxes to illustrate this choice, which seem to be “either/or” (and not, for example, “both”).
Just strictly in terms of programming and web forms, if Leon does mean “either/or” — maybe he should use “radio buttons” and not “checkboxes” […]
What programmers call radio button logic is related to what physicists call exclusion principles, both of which fall under a theme from the first-linked post above. As I wrote there, “taking minimal negations as primitive operators enables efficient expressions for many natural constructs and affords a bridge between boolean domains of two values and domains with finite numbers of values, for example, finite sets of individuals”.
To illustrate, let’s look at how the forms mentioned in the subject line have efficient and elegant representations in the cactus graph extension of C.S. Peirce’s logical graphs and Spencer Brown’s calculus of indications.
Keeping to the existential interpretation for now, we have the following readings of our formal expressions.
Take a look at the following article on minimal negation operators.
The cactus expression evaluates to true if and only if exactly one of the variables is false. So the cactus expression says exactly one of the variables is true. Push one variable “on” and the other two go “off”, just like radio buttons. Drawn as a venn diagram, the proposition partitions the universe of discourse into three mutually exclusive and exhaustive regions.
Refer now to Table 1 at the end of the following article.
Figure 1 shows the cactus graph for
Now consider the expression
Figure 2 shows the cactus graph for
If is true, i.e. blank, the expression reduces to so we have a partition of the region where is true into three mutually exclusive and exhaustive regions where respectively, are true.
If is false, it is the unique false variable, meaning and and are all true, so none of are true.
We can picture this as a pie chart where a pie is divided into exactly three slices
It is the same thing as having a genus with exactly three species