Wednesday, May 30, 2012
One screenshot
This is a screenshot from the movie, "ZULU" distributed around 1964. Awsome film about 19th century South African colonialism conflicts. All analog. No digital.
Thursday, May 24, 2012
truth tables
For (A AND B)
If A false true
---------------------
B | A AND B
false | false false
true | false true
**************************
For (P OR Q)
If P false true
---------------------
Q | P OR Q
false | false true
true | true true
**************************
What about the case in which P is false and Q is true? In a sense we have no evidence
about the implication as long as P is false. Logicians consider that in this case the
assertion P IMP Q is true. Indeed, the proposition P IMP Q is considered vacuously true
in the case where P is false,...
For (P IMP Q)
If P false true
---------------------
Q | P IMP Q
false | true false
true | ? true
**************************
vacuously true or, "The Emporer's New Clothes", white lies, etc.
"Every element of the empty set is also an element of {1,2}" is said to be true,
when in fact there aren't any elements in the empty set.
**********************************************************************************************
For (A AND B) IMP B
If A false true
--------------------
B | (A AND B) IMP B
false | true true
true | true true
...the proposition (A AND B) IMP B is true regardless of what A and B stand for.
ie. a tautology.
Taken without permission from from:
-http://www.cs.cornell.edu/Courses/cs3110/2011sp/lectures/lec13-logic/logic.htm#2
Saturday, May 19, 2012
Laws of Thought
- Laws of Thought
-
Identity
Whatever is, is
Every A is A.
EXISTS A
A=A
A <-> A
-
Contradiction
Nothing can both be and not be
Nothing can be A and not A
Everything cannot both be and not be
Everything cannot be A and not A
A IFF A
A XOR !A
A >< !A
-
Excluded Middle
Everything must either be or not be
Everything is either A or not A.
Nothing can be neither A nor not A
A OR (NOT A)
A | !A
-
Subscribe to:
Posts (Atom)