Better Gutenberg
Free, beautifully formatted public-domain ebooks

Giant Brains; or, Machines That Think

by Edmund Callis Berkeley

78 of 126 · Contents · Download EPUB

Table 12

UnitName of
Switches
MarkKind of
Switch
Switch Settings
3StatementV₁ to
V₁₂
DialStatements 1 to 12 or
constant T or F
2Statement
denial
~SnapAffirmative (down)
or negative (up)
4Connectivek₁ to
k₁₁
Dial∧ (and),
∨ (or),
▲ (if-then),
▼ (if and only if)
8Connective
denial
~SnapAffirmative (down) or
negative (up)
5AntecedentA₁ to
A₁₁
DialV or various k’s
6ConsequentC₁ to
C₁₁
DialV or various k’s
7StopS₁ to
S₁₁
SnapNot connected (down)
or connected (up)

The first step in putting a problem on the machine is to express the whole problem as a single compound statement that we want to know the truth or falsity of. We express the single compound statement in a form such as the following:

V k V k V k V k V k V k V k V k V k V k V k V where each V represents a statement, each k represents a connective, and we know the grouping, or in other words, we know the antecedent and consequent of each connective.

For example, let us choose a problem with an obvious answer:

Problem. Given: statement 1 is true; and if statement 1 is true, then statement 2 is true; and if statement 2 is true, then statement 3 is true; and if statement 3 is true, then statement 4 is true. Is statement 4 true?

How do we express this whole problem in a form that will go on the machine? We express the whole problem as a single compound statement that we want to know the truth or falsity of:

If [1 and (if 1 then 2) and (if 2 then 3) and (if 3 then 4)], then 4

The 8 statements occurring in this problem are, respectively: 1 1 2 2 3 3 4 4. These are the values at which the V switches (the statement dial switches, Unit 2) from V₁ to V₈ are set. The 7 connectives occurring in this problem are, respectively: and, if-then, and, if-then, and, if-then, if-then. These are the values at which the k switches (the connective dial switches, Unit 4) from k₁ to k₇ are set.

A grouping (one of several possible groupings) that specifies the antecedent and consequent of each connective is the following:

1and1if-then2and2if-then3and3if-then4if-then4
||||||
k₂k₄k₆
||||
k₁k₅
||
k₃
||
k₇

The grouping has here been expressed graphically with lines but may be expressed in the normal mathematical way with parentheses and brackets as follows:

{[ 1 and (1 if-then 2)] and [(2 if-then 3) and (3 if-then 4) ] } if-then 4.

So the values at which the antecedent and consequent dial switches are set are as shown in Table 13.

← Back to Giant Brains; or, Machines That Think

Scroll to Top