The idea of software being eternal is rubbish, not least because software isn't its code but its "identity" which comes down entirely to the actual use of langu

The idea of software being eternal is rubbish, not least because software isn't its code but its "identity" which comes down entirely to the actual use of language (including all the branding and marketing, all the live demos and discussions over drinks after conferences). The words "Napoleon Bonaparte" have a referent in the real world, just not in the present - does Napoleon Bonaparte exist? Usually we instead say he "existed". Incidentally, this is why I agree with the author that criteria 1 and 4 aren't actually necessary for non-existence of a piece of software. Even if lots of people, authors or otherwise, remember a piece of software, the software is gone once it can no longer be said to be used anywhere. In that case we would say that the software "existed".