This Day in Philosophy — 12 August: IBM unveils the personal computer

On 12 August 1981 IBM put on sale the personal computer it had given the model number 5150. It cost $1,565, and it held an Intel 8088 processor running at 4.77 MHz and between 16 and 256 kilobytes of memory.

By today's measure a modest machine. But the importance of the event lies not in its specifications; it lies in where computing power was moved to.

From the institution to the individual#

Until 1981 the computer was an institutional instrument: owned by universities and large companies, kept in a room of its own, operated by specialists. The IBM PC brought that power down onto a desk.

The philosophical consequences of the shift were seen more slowly than the technology itself.

Is the mind a computer?#

As the computer spread, it changed the vocabulary of the philosophy of mind as well. From the middle of the twentieth century functionalism had defended this thesis: mental states are defined not by the matter they are made of but by the functions that connect inputs to outputs. Just as a programme is independent of the hardware it runs on.

As computers came into every home, the analogy also became intuitively graspable. But the objections fed on the same analogy: John Searle's Chinese Room thought experiment set out to show that manipulating symbols according to rules does not produce understanding.

The extended mind#

Another line is directly bound up with the arrival of the personal computer in ordinary life. Andy Clark and David Chalmers's paper of 1998, The Extended Mind, asks this: a note in a notebook, a contacts list on a telephone, a file on a computer — are these outside the mind, or part of it?

The criterion the authors propose is functional. If an external record plays the role that biological memory plays, and plays it reliably enough, there is no principled ground for counting it as outside the mind.

The thesis could not have been written in 1981. For it to be written, the instrument of computation had to fit into a pocket.

Whose knowledge?#

The third consequence falls on the line Jean-François Lyotard foresaw in 1979: knowledge is progressively reduced to what can be computerised, and turns into a commodity that is bought and sold. The network, the search engine and the cloud that followed the personal computer accelerated the process.

The question asked in today's argument about artificial intelligence — who trains the models, who gathers the data, who owns the output — stands at the end of the road that opened on 12 August 1981.