Does the word "and" always mean a logical (boolean) operation?

Solution 1:

Does the word “and” always mean a logical (boolean) operation?

Certainly not, a quick glance at the dictionary demonstrates that the use of and is not limited to a boolean operation:

conjunction

1.0 Used to connect words of the same part of speech, clauses, or sentences, that are to be taken jointly:
bread and butter
they can read and write
a hundred and fifty

1.1 Used to connect two clauses when the second refers to something that happens after the first:
he turned round and walked out

1.2 Used to connect two clauses, the second of which refers to something that results from the first:
there was a flash flood and by the next morning the town was under water

1.3 Connecting two identical comparatives, to emphasize a progressive change:
getting better and better

1.4 Connecting two identical words, implying great duration or great extent:
I cried and cried

1.5 Used to connect two identical words to indicate that things of the same name or class have different qualities:
all human conduct is determined or caused—but there are causes and causes

1.6 Used to connect two numbers to indicate that they are being added together:
six and four makes ten

1.7 archaic Used to connect two numbers, implying succession:
a line of men marching two and two

2.0 Used to introduce an additional comment or interjection:
if it came to a choice—and this was the worst thing—she would turn her back on her parents

2.1 Used to introduce a question in connection with what someone else has just said:
‘I found the letter in her bag.’ ‘And did you steam it open?’

2.2 Used to introduce a statement about a new topic:
and now to the dessert

3.0 informal Used after some verbs and before another verb to indicate intention, instead of ‘to’:
I would try and do what he said

ODO

And is a conjunction connecting two related units, and the connection is not necessarily boolean:

... for the purpose of encouraging immigration and increasing the trade in the products of Michigan, or ...

The larger context informs of the relationship between encouraging immigration and increasing the trade:

The boards of supervisors of the several counties may levy a special tax on the taxable property within their respective counties for the purpose of creating a fund; or appropriate out of the general fund an amount to be used for advertising agricultural or industrial advantages of the state or county or any part of the state, or for collecting, preparing or maintaining an exhibition of the products and industries of the county at any domestic or foreign exposition, for the purpose of encouraging immigration and increasing the trade in the products of Michigan, or advertising the state and any portion thereof for tourists and resorters.

Recognizing the legislative source, and the productive analysis of parallelism, the exhibition mentioned in the larger context seems to have a three-fold purpose: immigration and trade or tourism. The conjunction and seems to be "boolean" in reference to the purpose--both are included together.

It is not necessarily "boolean" in reference to outcome. At some expositions, the the exhibit may effectively encourage immigration. At some expositions, the the exhibit may effectively increase the trade. At some expositions, the the exhibit may accomplish both.

Interestingly, the or presses the and toward a boolean interpretation in reference to the purpose. By contrast with the conjunction and, the conjunction or sets the advertising part of the there-fold purpose apart as an alternative to the pair: encouraging immigration and increasing the trade.

Still and would not necessarily have a strictly boolean function in reference to the outcomes. At any exposition, the the exhibit may fulfill any combination of the listed purposes--which were linguistically presented as a single three-fold purpose.

Conclusion:

The semantic complexity of purpose, rooted in the complexity of human reasoning and interaction, transcends a simple boolean arrangement. Unless they anticipate litigation, both the average writer and the average reader can manage this complexity without the need for precise boolean logic. Though this legislative language likely anticipated litigation, it remains a matter of subjective judgement to determine the "purpose" of an exhibit.

Solution 2:

Language can't be squashed into boolean logic. Nor are the meanings of phrases dependent on their fulfilment in the real world.

There are lots of cases where and can be used with essentially the same meaning as or, such as

Our dinner choices are pizza or curry.
Our dinner choices are pizza and curry.

This is because neither and nor or have the same meanings as their corresponding roles in logic. In language they are both conjunctions. And is the most unmarked conjunction; it means there are two things which are related together somehow. Or is more marked and presents the two ideas specifically as alternatives.