Eliza is a very simple program and could not be considered intelligent by anyone who understands the program. What the program does is searches the judge's phrase or question for key words such as "friend". When it has found a key word it will respond with something like "Do you often think about your friend?". When Eliza is asked a question she will reply with "Does that question interest you?". These types of strategies enable Eliza to fool someone for a short period of time, however, once you understand how the machine works it is easy to confuse her. When asked "You"re not answering my question are you?", Eliza cannot deal with the phrase and her reply does not make any sense: "Why do you say your question are I?". It is obvious that it will take a much more sophisticated approach than was used to make Eliza. .
One of the main criticisms is to do with the fact that machines can't make mistakes. Turing introduces an important distinction between "errors of functioning" which would be mechanical faults that are wrong with the machine, and "errors of conclusion", an example of which would be adding up some numbers incorrectly. Humans make many errors of this sort and Turing points out that there's no reason why machines shouldn't also. If the computer is programmed in the same way as a calculator, then it will always give the right answer to addition problems. But if instead it is programmed to do sums the way a human might then it would probably answer some maths problems incorrectly. .
Another criticism is that a computer can only have a fixed pattern of behavior; it can only do what we program it to do. What the computer does depends on what its program tells it to do. But that doesn't mean that the computer's behavior will always be fixed and rigid, in the way the Eliza program's responses seem fixed and rigid. Computers can also be programmed to "learn from their mistakes.
