# An Interview with Stephen Wolfram

**Paul Wellin, Mathematica in Education 2 (1993) 11-16.**
Stephen Wolfram is certainly no newcomer to our readers. As founder and president of Wolfram
Research, Inc., he has been involved in almost every aspect of the phenomenal growth of this
five year old company. Wolfram's science career began as a research physicist and quickly
led to areas in mathematics and computer science. He is the recipient of numerous awards and
honors, among them a MacArthur Prize Fellowship in 1981.

In this interview, conducted in a small cafe in Northern California, Wolfram discusses his educational background, some of the history of

*Mathematica*, and his view of its role in education. His opinions on the current state of mathematics and computer science education will be sure to disturb some, while others will find confirmation of what they already knew or suspected.

**PW:** Let's start out talking about your own education. What originally got you involved in science and math?

**SW:** Well, I went to fine English schools, and learned lots of useful things there about how to write good English prose and so on. But my interests in science had pretty much nothing to do with my official school education. As it happens, I got interested in science very young—by the time I was ten, I was already reading lots of physics books. Mostly what happened was that I would get excited about particular areas of science, then I would try to read everything I could about those areas. All along, the thing that got me really excited was looking at problems that hadn't been solved before. It turns out that when you are fourteen years old and thinking about physics, it isn't too hard to find problems that—at least as far as you know—haven't been solved before. I suppose the approach actually worked out fairly well—I started publishing physics papers when I was fifteen.

**PW:** You went to Oxford for college, but never finished there?

**SW:** That's right.

**PW:** So what led from there to Caltech?

**SW:** I was pretty much on the track of doing particle physics research, and being a physics undergraduate at Oxford wasn't a particularly useful environment in which to do particle physics research. Since I had the opportunity fairly easily to go to graduate school in the U.S., I decided to do that and I chose to go to Caltech.

The first year that I was at Caltech was the year that I had the highest rate of publishing papers of any time in my life. I actually think that on average, I was turning out a particle physics paper every few weeks. My main conclusion was that I did in fact know how to do particle physics research, so I collected together some of those papers and made a Ph.D. thesis out of it. I ended up getting my Ph.D. when I was just 20. In later years, I've realized that it was a big mistake not to make the effort to get my Ph.D. a few weeks earlier: it would be so amusing to say that one got one's Ph.D. when one was a teenager!

Anyway, after I got my Ph.D. I started thinking about doing things other than particle physics. At the time, I was involved in doing various particle physics calculations which involved very complicated algebraic expressions. I ended up trying to use Macsyma® to do these things. I had already been using Macsyma for several years for a variety of purposes. But my big disappointment was that after having written an incredibly ugly giant piece of code to do particle physics calculations, it in the end didn't work properly because of various limitations in Macsyma.

As a result of that experience, I decided that it should be possible to do something better than Macsyma. So my first step was to talk to the folks who had originally written Macsyma and try to persuade them that it was time to build a second generation system. What ended up happening, though, was that the older people who were involved in the project said, 'Well, you're probably right that we could do a lot better if we started again, but we're too old to consider doing that.' The younger people said, 'No, no, Macsyma is the best thing you could possibly do along these lines—you could never do better.' I didn't really believe that, and so I embarked on what became the SMP project, which was an effort to build a really powerful algebraic computation system. One of the very important things that happened in the course of building SMP was that I realized that there was a much richer style of programming that could be used when doing symbolic computations—rather than the Pascal-Algol-Fortan-like programming that was for example, built into Macsyma.

**PW:** Was your primary interest at this point to use SMP for particle
physics or did you have broader goals?

**SW:** Well, it was pretty clear that just to do particle physics,
one was going to have to have a very broad range of capabilities. And
if one was going to go to all the effort to build such a system, the system
better be as general as possible.

**PW:** The early computer algebra systems—Macsyma, SMP, etc.—were they used purely as research tools or was there some notion that
they might be used in the classroom also?

**SW:** At that time it was not really practical to think of using
these things in the classroom. SMP was built to run on the then-emerging
class of mini-computer systems such as VAXes, and
VAXes were in the multi-hundred thousand dollar price range, so it wasn't
realistic to think of those things being used in a serious way in the
classroom.

**PW:** How did the jump from SMP to *Mathematica* come about?

**SW:** After I finished being involved in the SMP project, I got
interested in trying to solve what I think is one of the more important
fundamental problems in science—how complexity arises in nature. I worked
for a number of years on that, and made rather good progress, using what
one can think of as an experimental mathematics approach: taking simple
computational systems and seeing what they do, and trying to develop theories
on the basis of those observations. One of the things that happened in
doing that, was that I realized that the main limiting factor in the science
I was doing was the time it took to prepare each experiment. I think I'm
a fairly good C programmer—by now I've written a significant fraction
of a million lines of C code—but it was still taking me many hours to
set up a particular experiment by creating a new C program. One of the
things that I realized was necessary to make more progress in that kind
of research was to develop a system that could allow one to interactively
do high-level programming to specify one's problems in a way that was
as close as possible to how one thought about them, and not to have to
go through this rather painful step of writing fairly low-level C programs.
So that was one issue I was confronted with.

The other thing was that around 1986, I realized that there were going
to be personal computers powerful enough to run a fairly general, fairly
sophisticated computational system; I thought that was a very interesting
intellectual and business opportunity. So I decided to build *Mathematica*.
As it turned out, the timing was very
good. At the time when *Mathematica* came out, we were *just*
on the part of the curve where Macintoshes, and soon PC's, were powerful
enough to run that kind of thing.

There were a lot of issues that came up in thinking about how *Mathematica*
could be applied to education, and whether it would be applied to education.
In the computer industry, it was believed at that time that selling programs
for the educational market was a waste of time—that this was not a business
proposition. In fact, that belief even extended to selling programs to
the research part of the university community. Much of the early thinking
about *Mathematica*, as it was presented to the computer industry,
was how this should be used by engineers, and not what could happen with
it in academia. In fact, I consider one of the business achievements of
*Mathematica* to show that it is in
fact a meaningful business proposition—to make programs where significant
effort is put in to meeting the needs of academia.

I didn't know how effectively *Mathematica* would catch on in education.
In fact, I was at first pessimistic about the number of years it would
take before there was really significant usage of *Mathematica* in
education. What I thought in the beginning, was that in five to ten years,
there would be significant stuff going on with *Mathematica* in education.
I was very pleasantly surprised that within one or two years the early
adopters were already doing very interesting things with *Mathematica*.

**PW:** Were there more institutions involved in the early development processes, other than the University of Illinois?

**SW:** There were certainly many research users, many of whom do
teaching as well. I think that there was a surprisingly quick realization
that *Mathematica* was relevant to the whole calculus reform movement.
We were very lucky, though, that Horacio Porta and Jerry Uhl at Illinois
jumped into this whole thing as quickly and as effectively as they did.

**PW:** The state of science and math in this country is really quite perplexing.
On the one hand, we have some of the finest research institutions in the
world. On the other hand, it is widely recognized that the *teaching*
of these subjects is sorely in need of repair. Our students often can't
apply their knowledge to relevant problems, let alone use a computer to
do any significant work in science.

**SW:** I remember a couple of early
experiences interacting with the 'computers and education' crowd at conferences.
The experiences varied—from me being very pleasantly surprised at how
quickly people seemed to be catching on to the potential for this kind
of thing, to complete horror at the fact that people like the ones I was
seeing were actually teaching young Americans about science or mathematics.

I continue to be amazed that, in the math educational process, there is such an emphasis on, as I see it, highly esoteric issues of pure mathematics. The notion of proof is an interesting one, but very few people in adult life so to speak, "do proofs." That kind of thinking is, I think, most prevalent among mathematicians and lawyers. I think the emphasis on that kind of thing in mathematics education is a consequence of some kind of trickle-down effect from the influence of mathematics research in this century.

**PW:** As a mathematician, I might argue that you can rest assured
that the mathematics you use in your science is secure because the foundations
have been tidied up by the diligence of the mathematical community.

**SW:** I guess I have a stronger belief in 'truth' than I do in
'proof.' As experimental mathematics becomes more widespread, the divergence
between truth and proof, in mathematics, will become larger. If you look
at any area of science, there are far more experimentalists than theoreticians.
Mathematics is the unique exception to this trend. It is my very strong
suspicion that within a few decades, things will have switched around—there will be, as there are in physics, more experimental mathematicians
than theoretical mathematicians. With luck, that change will reflect itself
in parts of the educational process of mathematics—and I think that
will be very healthy, because in my opinion, the fraction of people who
are in a position to appreciate pure mathematics is very small. I don't
think I'm one of them, for example, even though I am certainly a fairly
serious user of mathematics. The idea of presenting mathematics in education
as being about proofs is really the wrong thing.

**PW:** Is this why computer science and mathematics departments
have diverged so strongly in the recent past?

**SW:** One of the biggest mistakes of research mathematics in America
in the last 50 years, has been to let computer science get away. If you
look at what was done when computing was young, there was a strong and
definite strand of computing that was essentially part of mathematics.
The mathematicians rejected it: this was a big mistake. While there is
a certain track of computer science which is basically
computer engineering, the fact that computing and mathematics ended up
being adversaries rather than being close intellectually, was a big mistake
of the mathematics community.

When *Mathematica* was quite young, and I talked to people in the
computer industry about doing mathematics on computers, they said to me,
'Why would anybody want to do that?' It's quite ironic, considering that
in the early days of computing with von Neumann, Turing, and others, one
of the original conceptions (at least one of the major tracks) was that
one was building these machines to automate mathematics. There was another
track saying that one was building these machines to automate what the
census bureau does, which is a separate bookkeeping area. But by the
time personal computers had come out in the late 70's and early 80's,
the computer industry had this idea that what computers were used for
was word-processing, spreadsheets, etc., and the notion that one could
use computers to do mathematics was bizarre.

**PW:** Even with the early computational number theorists such as
D.H. Lehmer at Berkeley?

**SW:** I'm afraid that none of the leaders of the computer industry
have probably ever heard of D.H. Lehmer. But there were certainly a small
number of mathematicians who had used computers to do essentially experimental
mathematics for some time. Even in academic mathematics, though, these
people were a tiny corner of the mathematics community.

Recently, I happened to be studying the history of computing, and I've
really been struck by the fact that in the early writings about computing,
particularly in accounts to the general public of computing, it was always
about these machines that are capable of automating mathematics. One of
the achievements of *Mathematica* has been to demonstrate that indeed,
computers are useful for mathematics. I think it was an unfortunate fact
that the mathematics community itself had been so much against computers.

**PW:**
There has been discussion (and hope by some) that mathematics and the
rest of the sciences will tend to become less distinct. They are becoming
more and more involved in similar computational tasks, albeit on different
problems.

**SW:** With the current system of science in America, I don't see
any mechanism to reduce the rigidity of it. I think it's a hell of a pity,
because more good science and more useful science could be done if there
was less rigidity. Over the 15 years or so that
I've been doing science in America, I've just seen increasing rigidification
in the funding agencies and the universities. Everything has to fit into
a mathematics department or a physics department or whatever else. The
early hope that computing would cut across these things and develop more
interdisciplinary approaches, really hasn't panned out.

There's a question that I really don't know the answer to: "Is 'computational science' something that there should be departments of?" Or, "Is 'computation' really a tool that should get mentioned in the educational process of all these different areas?" That's sort of a similar question to how calculus should be dealt with, because calculus can either be taught in a mathematics department as the domain of mathematics, or it can be distributed among the engineering and physics departments. That's worked differently at different places.

I think that in the case of learning about *Mathematica*, for instance,
that question again comes up. Should *Mathematica* be taught as a
course unto itself—perhaps in the computer science department, perhaps
in the mathematics department? Or should it be the case that if you are
trying to teach about *Mathematica*,
you spend the first two weeks of the class talking about that, and specialize
your discussion to the particular physics course or whatever you are going
to give. My guess is the way things will evolve (or should evolve), is
that there will be one central place where people learn *Mathematica*,
just as there is one central place where people learn calculus, and then
they can go out and apply it.

**PW:** It would certainly be a more efficient way to do things.

**SW:**
Yes, but in terms of the rigidity of present-day science, there are two
places where there are issues. One is in the research area, the other
is in the educational area. To be honest, I see more chance for change
in the educational area than in the research area. The research area is
so dependent on the structure
of funding and things like this, that
I don't see that being something that will change quickly.

In the educational area, I think it is much more plausible that computational science courses will develop that do cut across the very rigid boundaries that exist right now. That seems to be a very encouraging thing.

**PW:** At present, what is the breakdown of educational *vs*.
research users of *Mathematica*?

**SW:** That's a bit of a difficult question to answer. Because when
you have a class that uses *Mathematica*, how do you count the individual
students that are going through there? I think that about 40% of the number
of copies of *Mathematica* that are out there are in the educational
sector. About 23% of the revenue that comes in from sales of *Mathematica*
comes from the educational sector.

When I say educational sector, I mean colleges, high schools, and universities
which includes much research usage of *Mathematica*. It's hard to
be able to come up with exact figures.

**PW:** I noticed a rather long debate on the nets recently about
the current 'role' of *Mathematica*. Some people were arguing that
presentation features should not be focused on—that all work should
go into algorithm improvement. I am sure that a similar argument could
be put forth about the *Mathematica* language itself as well. In
light of your previous statement about who is using *Mathematica*,
what is your view of its present role?

**SW:** In terms of algorithm development, I am really very satisfied
with the point we're at and the rate at which things are progressing.
My big test for these things in terms of, for example, algebraic algorithms,
is to be able to clearly say that if there is an integral you can think
about doing, then *Mathematica* will be able to do it better than
any person, or any other computer system. This is the same kind of issue
as has arisen in playing chess. There's a point at which eventually the
computers are actually just *better* than people at doing it. And
we're pretty close to that point with many kinds of integrals.

One area in which you will see some significant development is in the
area of *Mathematica* interactive documents. People have talked for
quite a few years about 'hypertext' and 'multi-media' and electronic books,
and so on. But there really isn't a hell of a lot out there that actually
makes any sense—except for *Mathematica* Notebooks. The fact is
that for all the hype that has gone into the idea of electronic books
in the publishing community and the computer industry, the one example
of this that actually seems to be working is *Mathematica* Notebooks
.

There are some things you'd like to be able to do with *Mathematica*
Notebooks that you can't do now. For example, including beautiful typeset
mathematical equations. That is something we are going to make work, and
I think in a very nice way.

**PW:** I'd like to turn to *Mathematica* as a programming language
entity. From an educational point of view, would you put the *Mathematica*
language on a par with Fortran or Pascal?

**SW:** People might attack me for immodesty, but I think in the
present day and age, if you're teaching general people about programming
computers, *Mathematica* is far and away the best programming language
to use—and I'll tell you why. There are a certain set of people, who
when they are grown up, will write things like compilers. Those people
need to know C and they need to know how to build parsers. But in the
world right now, there are probably only 50 people who write compilers.
And probably most of them learned what they needed outside of school,
anyway.

What one should be trying to teach when one teaches people about programming, is two things. First of all, one should teach them the practicalities of actually doing programming that they might use later on in life. Second of all, one should teach them concepts about what it means to program a computer, and what ways of thinking programming involves.

Taking the second of those things first, teaching the concepts of programming in a language like C or Pascal, is crazy. You can only teach a very small subset of what is known today about the ways it makes sense to do programming.

**PW:**
Well, most computer science departments get around this by requiring their
students to learn half a dozen different languages.

**SW:** People who just take a CS 101 type course, they'll typically
learn C or Pascal. The pity about that is, knowing about symbolic computation,
functional programming, transformation rules, what it means to do graphics
programming—they don't get any of that stuff in C or Pascal. I think
that's a real pity. Knowing the details of how to do pointer manipulation
in C and how to do memory management is absolutely beside the point in
the modern world.

It's a strange anomaly in the history of programming languages that over
the last 20 years, there's been an incredible transformation in the computer
hardware systems that exist, and in the kinds of people who use computers
and interact with them on a daily basis. Yet in that period
of time, the world of programming languages has changed
almost not at all. I think it *will* increasingly change. Already,
there are many application programs that have little programming languages
attached to them. Some of them are BASIC-like, some of them are like other
kinds of things.

Even if you are not actually
going to program in *Mathematica* later, using *Mathematica*
as the language to learn about the ideas of programming is the right thing
to do, because it is the *broadest* of the programming languages.
So you can actually get familiar with all these different concepts in
this one environment.

Another thing that is very significant is that in *Mathematica*—because there is no really clear line between its programming side and
its computational side—you can immediately do things where you can see
the results. You can *gently* go into programming. The idea that
students have to learn #include<stdio.h>, etc.—this kind of
strange incantation of having to write at least 20 lines of code to get
their first C program working—is really unfortunate. It gives them the
idea that programming is much more of a black-magic kind of thing than
it actually is. That's a pity.

In a sense, BASIC was, from that point of view, a much better kind of language. But from the point of view of understanding the concepts of programming, it was fairy weak.

If you learn C, it's a significant distance between knowing C and being
able to simulate a pendulum, for example. Whereas, in *Mathematica*,
if you know the concepts, it is very easy to go and apply that to your
physics course right away.

One of the areas that I am most enthusiastic about in terms of the educational
development of *Mathematica*, is this area of using *Mathematica*
as an educational programming language. I am particularly hopeful that
over the next couple of years, there will be a number of books which will
help present *Mathematica* as an educational programming language.
My own take on how these things are taught right now is that, increasingly,
courses are starting to be taught in scientific computing. *Mathematica*
is
definitely a language that should be used for that. It would be crazy
to use anything else at present.

**PW:** The argument you will get from the computer science department
will be, 'Our students are not going to be using this language to program
when they get out in the real world.'

**SW:** I think that's not really a valid argument. First of all,
20% of the users of *Mathematica* are computer scientists. If you
look at the software development companies, I would say that all of the
big ones have significant numbers of copies of *Mathematica*. All
of them use it, particularly for prototyping algorithms. When they are
building the final production version of something, they'll often translate
it into C and use low-level stuff. But in terms of algorithm prototyping
and understanding the structure of algorithms and programs, *Mathematica*
is not only a *good* tool to use, it is also the tool that actually
*is* being used.

Another argument that people give is, 'Gosh, the students should really understand at a low-level what the computer is doing.' Well, I don't disagree about that. You can also say that about all kinds of technical areas. You can say that about mathematics. People shouldn't use calculators because they should understand at a low-level how to do square roots and so on. Well, my contention is that the way you really understand how to do square roots is by using a calculator and seeing what happens, and that after you really understand what good they are and have experimented with them, then you are finally motivated to maybe ask, 'How did the calculator manage to do this calculation?' In the case of square roots, I don't know! I never learned how to take square roots by hand. A couple of times in my life I have studied the algorithm for doing this to implement on the computer, but it is not something I remember or think is significant.

The same thing is true in computing. Knowing how memory allocation is done is something that, once you've used computing a lot, you could then get interested to see what the foundations are. If every time we wrote a program, we had to think about what would be the physical addresses that our program will be loaded into memory at—or worse, what voltages would be going high and low in certain transistors in the microprocessor—we wouldn't get anywhere. The thing that has made computing really take off is the fact that software can be built in layers, and you can assume that there is a lower layer which you really don't have to worry about.

It
would be extremely foolish for the students to decide that this layering
effect of software is a bad thing. Quite to the contrary, in terms of
understanding, I think the things which are most valuable to teach in
a computer science course are the *concepts* of programming, and
those are not well taught by going down to the level of transistors, or
for that matter, to the level of C or Pascal.

I must say that I am not a great enthusiast of the academic computer science world. There certainly are some really good things which border on mathematics that are being done there, but I think it is a sign of the weakness of the field when its major concern is defending itself from the outside world. Those fields like physics for instance, that are really quite self-confident and at peace with themselves, don't worry a hell of a lot about defending themselves from statements such as, 'This isn't physics, it's engineering, or something else.'

**PW:** Well, I think you have to remember that computer science
is a very young discipline.

**SW:** It is, but I think it's made a lot of mistakes on the way.
They worry, 'How can we teach people about commercial software,' for example,
even though commercial software is what it's about in the world at large.
To teach students a toy spreadsheet is stupid. You might as well teach
them *1-2-3*® or Excel®, because that's what they'll be using.

It is a strange and somewhat unhealthy feature of computer science that it is mostly trying to defend itself from the real world, rather than thinking about how it can contribute to the progress of the real world and to educate students to interact with that world.

**PW:** What are the changes that you envision for *Mathematica*
and Wolfram Research in the next five years?

**SW:** Certainly our strategy with *Mathematica* over the years
to come will go in several tracks; one of those tracks will be to push
the programming language part of *Mathematica* as a separate entity,
independent of the mathematical and calculational capabilities of the
system. How exactly that will play out in the computer industry and what
all of the arrangements and licensing issues will be, we don't yet know.

One
of the issues I mentioned earlier was this whole question about interactive
documents—*Mathematica* Notebooks built on top of *Mathematica*—and how those things will develop. One of the big issues is, when people
write these things, how are they going to be distributed? With *MathSource*
we started trying to address that issue. I think one of the things that
we'll see is this notion of publishing with *Mathematica*. This will
be increasingly important. In the educational arena, this migration from
printed textbooks to on-line *Mathematica* Notebooks will be something
that we'll see in the next few years.

In terms of *Mathematica* itself, there will certainly be incremental
improvements in the details of the algorithms. There are a number of things
that will get developed, such as typesetting capabilities, and so on.

One
of the things we've seen in education recently, is a transition from use
on individual machines to the existence of educational labs that could
have *Mathematica* running on all the machines. Now, finally, we're
getting to the point where the generally used machines which exist in
universities are powerful enough to run *Mathematica*. That hasn't
been true until recently. There are a number of things that one will see
changing as we adapt, both technologically and from a business point of
view, to an environment where that's possible.