Free software is fine when it doesn’t cost much to develop and support. But you can’t expect to have a really vital long-term product and make it free. What we see a lot with Mathematica packages is that the first versions are free: they’re made by one or two people at a university or some such. But once the packages get serious—have real documentation, quality assurance, etc.—they have a real price. And the result is that money is made that supports the future development of the packages, and so on.

Perhaps you’re asking whether I think software should be distributed for free in general. I guess I think that intellectual property protection is a pretty good feature of civilized society. Now of course there are some people who think software development should always be paid for by the government or something, and then distributed free. Well, I tend to think that the less the government has to get involved in, the better. Let people who want software pay for it; it really doesn’t make sense to tax everyone in order to get software for a small segment of society developed. It’s really very selfish on the part of mathematicians or whoever to expect all the taxpayers out there to support their particular software interests.