Thursday, February 1, 2001
Quiz 2
Name: _______________________________
Two lenghts AB and CD are commensurable if
they can be measured by the same unit. Formally: if there exists a rational
number u and natural numbers x and y, such that u*x=AB and u*y= CD. (Lecture).
60 has many divisors (1, 2, 3, 4, 5, 6,
10, 12, 15, 20, 30, 60); it is also related to early calendars
(with 360 days); but, ultimately, the author does not know. (Barrow, page
65-67).
An argument is deductively valid, if it is impossible for the premises to be
true and
for the conclusion to be false at the same time (Lecture; FOL, p.24).
An argument where the truth of the premises
make the conclusion more likely to be true (Lecture).
A
A->B
---------- (Weston, page 47).
B