Introduction

HINT: Print these instructions and step through them with the program before you.

The program layout has a large, workspace, a menu bar, and a toolbar on the right with six buttons.

Connectives Used by program:

For conjunction:

(A&B)

For disjunction:

(A+B)

For implication:

(A>B)

For equivalence:

(A=B)

For negation:

~A

Truth Functions

• Click button on the toolbar..
  • In the text field of the dialog box enter a well formed logical expression..
  • EXAMPLE:
    • [(A&B)&C]=[A&(x+y)]
    • CAUTION: Make sure it is well formed before you close the dialog box.
    • NOTE: You can enter expression in lower case. No space between the characters.
  • Click the 'Accept' before the 'Close' button If the dialog box is too small for its message, drag the right edge of the box with the mouse when you see double arrow <->.
• Now there are two choices:
  • If you know the value of all or some of the variables:
    • Click button on the toolbar..
    • In the dialog box select values for the indicated variables. (The program uses # to designate an unknown value.)
    • Close the dialog box and study the problem. The values will appear below the expression. Logical connectives mark places where values have to be calculated. When you have decided what the next value should be, click to see if you are right.
  • Value of variables is not known :
    • Click button on the toolbar. .
    • Study truth table to see what the next value should be. The program calculates values by rows, one at a time, left to right and top to bottom .
    • Click the arrow button to see if you are right.
    • NOTE: If you wish to know whether the expression is a tautology, self-contradiction, or contingent, click the arrow button one more time after all the values have been calculated. A dialog box appears giving the answer. If the main logical connective is '=' and the dialog box evaluates the expression as a tautology, then the components to the left and right of '=' are equivalent. .

Truth Tables for Arguments:

• Click the top button on the toolbar.
  • Enter the argument on one line separating the premises with a single slash(/) and and separating the conclusion from the premises with two slashes(//).
  • Wrap all non-negated compound propositions with outer punctuation.
  EXAMPLE:

  1. A
  2. ~B
  3. A>B(wrap in parentheses)
  4. ~(B&C)(negated: do not wrap)
  5. C+(B&C)(wrap in brackets)
  6. ~[(B>A)+C](negated:do not wrap)
  /C+A(wrap in parentheses)

  Enter thus:
  A/~B/(A>B)/~(B&C)/[C+(B&C)]/~[(B>C)+C]//(C+A)

  • CAUTION: Check to see that what you have entered is correct.
    • Click the "Accept' .before the 'Close' button.
    • Decide what the next value assigned should be and click the arrow button to see if you are right.
    • Clicking the arrow button after the table is done will tell you whether the argument is valid or not.

Indirect Truth Table For Arguments:

• Enter an argument following the directions for truth tables for arguments.
  • Then click the arrow button (the fourth one down on the toolbar).
  • You know the rest of the drill. Have fun.

Using the built in exercises:

• Click on 'Exercises' on the menu bar.
• Select type of exercise.
• Except for your not having to enter the proposition, all is as above.
• The button will load the next proposition for you to work on.
• NOTE: For the inderect truth table problems hit the bent arrow and start on the second problem.

TRUTH TABLES

INPUT	OUTPUT
	and	or	if...then...	if...and only if...
P.....Q	P&Q	P+Q	P>Q	P=Q
T.....T	T	T	T	T
T.....F	F	T	F	F
F.....T	F	T	T	F
F.....F	F	F	T	T

NEGATION

INPUT	OUTPUT
P	~P
T	F
F	T

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