If a particular letter stands for a particular term in one part of an argument, it must stand for that same term throughout the argument. Abstract the form from the content, listing the premises first and the conclusion last. Beside the abstracted argument, set up the skeleton of the argument, noting that premises must be true and the conclusion false. With a pencil, try substituting terms into the skeleton that result in all true premises and a false conclusion. All hamsters are creatures who like to eat carrots.
All furry animals are creatures who like to eat carrots.
All dogs are animals . All dogs are mammals . All animals are mammals . This is not the case. In logic, as a general rule, do not infer any more than what is given.