What is a computer? Wikipedia currently gives the following definition:
A computer is a device that can be instructed to carry out an arbitrary set of arithmetic or logical operations automatically.
This definition is one that might be expected from a computer scientist. It is very broad and entirely functional, that is, it describes a computer strictly in terms of what it does.
People in other roles may conceive of a computer quite differently. Consumers (and their suppliers) tend to think of computers as a particular category of electronic device, one that is distinct from a calculator, a TV set, or a smartphone, although all those devices are computers in the functionalist sense.
This point arises currently in a pair of ads by Apple and Microsoft. Apple recently floated an ad suggesting that its iPad Pro is not merely a tablet but a computer. Behold!
Is a tablet with a keyboard a computer? Microsoft begs to differ, as made clear by the following discussion between Cortana and Siri, reported in a Microsoft Surface ad. Voilà!
Microsoft makes its case for the Surface only as a computer by referring to its possession of "more power", running "full Office", plus the presence of certain physical features such as a trackpad and external ports.
It seems that the Microsoft ad has a point: In terms of consumer categories, computers and tablets are different, though related, types of thing. Yet, the similarities between the iPad Pro and the Microsoft Surface (e.g., they both have keyboards now) make the distinction transient and hard to draw precisely.
So, can the essence of a computer be defined clearly and for all time? Or, is the category a historically contingent difference between product types, never clear and apt to change over time?