Computation is symbol manipulation on the basis of their shapes which is systematically interpretable.
Computational systems are symbol systems.
The success of AI in mimicking human cognition has encouraged some psychologists to think that due to a computer's and a human's functional indistinguishability, they are one and the same. The machine plays, fast - forwards and pauses the tape on the basis of rules which dictate every action dependent on its internal states. He achieved the deception by having subjects write to a 'penpal' which was actually a computer. We are investigating the formal properties, not the physical ones. A different piece of hardware with a different piece of software may be performing the same computation.