World's Smallest Electronic Brain

Miniac

World's Smallest Electronic Brain

Herein presented is a Do-It-Yourself plan for constructing a computer that will answer questions not resolvable by any other computing machine. Among its many advantages, MINIAC is (1) small enough to be carried in one's pocket; (2) inexpensive; (3) infallible; (4) easy to build; (5) often times found on the ground or sidewalk; (6) child's play to operate. 

To build a MINIAC: 

1. Obtain a penny. 
2. Write the words YES or NO on two pieces of paper and glue one to each side of the penny. Or mentally substitute Heads for YES and Tails for NO, or visa versa. 

To operate MINIAC: 

1. Hold MINIAC on the thumb and forefinger and ask it a question (e.g., Will it rain today?") 
2. Flip MINIAC and allow it to come to a rest
3. Note the answer, either YES or NO

Now MINIAC has given us either a true answer or a false answer. To determine which: 

1. Hold MINIAC as in operating instructions 1, ask the question: "Will your present answer have the same truth-value as your previous answer?" and flip
2. Note the answer, either YES or NO

Explanation: 

• Suppose MINIAC's answer to the second question is YES. 
• This is either a true answer or a false answer. 
• If true, then it is true that the answer to the first question has the same truth-value as the answer to the second question, hence the answer to the first question was a true answer; if false, then it is false that the answer to the first question has the same truth-value as the answer to the second question, hence the answer to the first question was a true answer. 
• In either case, if MINIAC answers YES to the second question, then its answer to the first question was a true answer. 
• If MINIAC answers the second question with NO, a similar line of reasoning shows that its answer to the first question was a false answer. 

Note: 

The electronic character of MINIAC is obvious from the fact that there are two free electrons in the outer shell of the copper atom. 

Credit: 
Vicious Circles and Infinity: A Panoply of Paradoxes, Patrick Hughes and George Brecht