I consider the computer to be the greatest physical innovation in my field - in any field for that matter, and for all human time. At the least, computers allow the efficient externalisation of logic. The more flamboyant contention is that the computer allows - or will someday allow - the externalisation of reason and thought.
The externalisation of logic (for example in networked embedded processors) transforms production and operation into a uniform programming exercise. This is a revolution that is ongoing and nowhere complete.
The externalisation of reason and thought gives us objective access to the fundamental issues of consciousness, identity and mind. At the same time, it allows us to push reason and thought beyond the limitations of biological mechanism, all the way to the limits of nature itself.