May 29, 2018 3:41 PM

Software as Adaptation-Executer, Not Fitness-Maximizer

In Adaptation-Executers, not Fitness-Maximizers, Eliezer Yudkowsky talks about how evolution has led to human traits that may no longer be ideal in the our current environment. He also talks about tools, though, and this summary sentence made me think of programs:

So the screwdriver's cause, and its shape, and its consequence, and its various meanings, are all different things; and only one of these things is found within the screwdriver itself.

I often fall victim to thinking that the meaning of software is at least somewhat inherent in its code, but that really is what the designer intended as its use -- a mix of what Yudkowsky calls its cause and its consequence. These are things that exist only in the mind of the designer and the user, not in the computational constructs that constitute the code.

When approaching new software, especially a complex piece of code with many parts, it's helpful to remember that it doesn't really have objective meaning or consequences, only those intended by its designers and those exercised by its users. Over time, the users' conception tends to drive the designers' conception as they put the software to particular uses and even modify it to better suit these new uses.

Perhaps software is best thought of as an adaptation-executer, too, and not as a fitness-maximizer.

Posted by Eugene Wallingford | Permalink | Categories: Computing, Software Development

May 27, 2018 10:20 AM

AI's Biggest Challenges Are Still To Come

Semantic Information Processing on my bookshelf

A lot of people I know have been discussing last week's NY Times op-ed about recent advances in neural networks and what they mean for AI. The article even sparked conversation among colleagues from my grad school research lab and among my PhD advisor's colleagues from when he was in grad school. It seems that many of us are frequently asked by non-CS folks what we think about recent advances in AI, from AlphaGo to voice recognition to self-driving cars. My answers sound similar to what some of my old friends say. Are we now afraid of AI being able to take over the world? Um, no. Do you think that the goals of AI are finally within reach? No. Much remains to be done.

I rate my personal interest in recent deep learning advances as meh. I'm not as down on the current work as the authors of the Times piece seem to be; I'm just not all that interested. It's wonderful as an exercise in engineering: building focused systems that solve a single problem. But, as the article points out, that's the key. These systems work in limited domains, to solve limited problems. When I want one of these problems to be solved, I am thankful that people have figured out how to solve and make it commercially available for us to use. Self-driving cars, for instance, have the potential to make the world safer and to improve the quality of my own life.

My interest in AI, though, has always been at a higher level: understanding how intelligence works. Are there general principles that govern intelligent behavior, independent of hardware or implementation? One of the first things to attract me to AI was the idea of writing a program that could play chess. That's an engineering problem in a very narrow domain. But I soon found myself drawn to cognitive issues: problem-solving strategies, reflection, explanation, conversation, symbolic reasoning. Cognitive psychology was one of my favorite courses in grad school in large part because it tried to connect low-level behaviors in the human brain connected to the symbolic level. AlphaGo is exceedingly cool as a game player, but it can't talk to me about Go, and for me that's a lot of the fun of playing.

In an email message earlier this week, my quick take on all this work was: We've forgotten the knowledge level. And for me, the knowledge level is what's most interesting about AI.

That one-liner oversimplifies things, as most one-liners do. The AI world hasn't forgotten the knowledge level so much as moved away from it for a while in order to capitalize on advances in math and processing power. The results have been some impressive computer systems. I do hope that the pendulum swings back soon as AI researchers step back from these achievements and builds some theories at the knowledge level. I understand that this may not be possible, but I'm not ready to give up on the dream yet.

Posted by Eugene Wallingford | Permalink | Categories: Computing

May 22, 2018 3:30 PM


This weekend, my family headed to St. Paul, Minnesota, to celebrate my younger daughter's graduation from college. The day served as a bookend to the day. seven years ago this fall when I dropped my older daughter off at college. Two beginnings, two endings -- and the beginnings they created.

Graduation day was emotional for me in a different way. It is wonderful gift to hear faculty and friends say such good things about your child. This is a young women I've always known to be special, and now we know some of the ways the rest of the world appreciates her. They appreciate some of the same things I appreciate, but they also know her in ways I do not and so can appreciate her ways I don't always have access to. Another gift.

Off into the world she goes to do her thing. To be honest, though, she's been out in the world for a long time doing her thing and making it a better place. It's one of the things I admire so in her, and in her big sister. I enjoy admiring my daughters as much as I do.

With both daughters out of college, I will miss the time we've spent visiting their college campuses. I tried to savor this weekend more knowing as I do how much I missed my older daughter's campus after she graduated. Of course, now I'll get to visit them in places like Boston and Minneapolis and get to know these cities better, through their eyes. Yet another gift.

Posted by Eugene Wallingford | Permalink | Categories: Personal

May 18, 2018 1:24 PM

Sharing Control

Sidney Lumet, in his book Making Movies, writes:

Arthur Miller's first, and I think, only novel, Focus, was, in my opinion, every bit as good as his first produced play, All My Sons. I once asked him why, if he was equally talented in both forms, he chose to write plays. Why would he give up the total control of the creative process that a novel provides to write instead for communal control, where a play would first go into the hands of a director and then pass into the hands of a cast, set designer, producer, and so forth? His answer was touching. He loved seeing what his work evoked in others. The result could contain revelations, feelings, and ideas that he never knew existed when he wrote the play. That's what he hoped for.

Writing software for people to use is something quite different from writing a play for audiences to watch, but this paragraph brought to mind experiences I had as a grad student and new faculty member. As a part of my doctoral work, I implemented a expert system shells for a couple of problem-solving styles. Experts and grad students in domains such as chemical engineering, civil engineering, education, manufacturing, and tax accounting used these shells to build expert systems in their domains. I often found myself in the lab with these folks as they used my tools. I learned a lot by watching them and discussing with them the languages implemented in the tools. Their comments and ideas sometimes changed how I thought about the languages and tools, and I was able to fold some of these changes back into the systems.

Software design can be communal, too. This is, of course, one of the cornerstones of agile software development. Giving up control can help us write better software, but it can also be a source of the kind of pleasure I imagine Miller got from working to bring his plays to life on stage.

Posted by Eugene Wallingford | Permalink | Categories: Software Development, Teaching and Learning

May 09, 2018 4:02 PM


In an old blog post promoting his book on timing, Daniel Pink writes:

... Connie Gersick's research has shown that group projects rarely progress in a steady, linear way. Instead, at the beginning of a project, groups do very little. Then at a certain moment, they experience a sudden burst of activity and finally get going. When is that moment? The temporal midpoint. Give a team 34 days, they get started in earnest on day 17. Give a team 11 days, they get really get going on day 6. In addition, there’s other research showing that being behind at the midpoint--in NBA games and in experimental settings--can boost performance in the second half.
So we need to recognize midpoints and try to use them as a spark rather than a slump.

I wonder if this research suggests that we should favor shorter projects over longer ones. If most of us start going full force only at the middle of our projects, perhaps we should make the middle of our projects come sooner.

I'll admit that I have a fondness for short over long: short iterations over long iterations in software development, quarters over semesters in educational settings, short books (especially non-fiction) over long books. Shorter cycles seem to lead to higher productivity, because I spend more time working and less time ramping up and winding down. That seems to be true for my students and faculty colleagues, too.

In the paragraph that follows the quoted passage, Pink points inadvertently to another feature of short projects that I appreciate: more frequent beginnings and endings. He talks about the poignancy of endings, which adds meaning to the experience. On the other end of the cycle are beginnings, which create a sense of newness and energy. I always look forward to the beginning of a new semester or a new project for the energy it brings me.

Agile software developers know that, on top of these reasons, short projects offer another potent advantage: more opportunities to take stock of what we have learned and feed that learning back into what we do.

Posted by Eugene Wallingford | Permalink | Categories: General, Software Development, Teaching and Learning

May 08, 2018 4:45 PM

"Tell Me Something You Learned"

I spent big chunks of the last two days grading final projects and final exams for my Programming Languages course. Grading exams is important but not a lot of fun, so I released a little tension on Twitter as thoughts popped into my head:

I love final exam answers that appear to be randomly generated from a list of terms learned in the course.
Also fun: code that appears to be randomly generated from a list of functions learned in the course.
... and then a student surprises me with a creative, efficient solution. I like those answers just as much.
Answer of the day so far: "Local variables help us be more ambiguous solving many problems at once."

I don't know what that means, but I love it.

I hope folks did not think I was "punching down". I know how stressful final exams are for most students, and I know how challenging a comprehensive final exam in this course is. Students have to write code, explain ideas, and connect ideas to code. It's tough. The tweets were just me having a little fun during what is otherwise a slow, laborious process.

This exam ended differently than any of the previous finals in this course. The final question, worth 5% of the exam grade, was this:

Identify one topic from the course that is not covered by an exam question but about which you learned something valuable. Write two to three sentences about what you learned.

I used to include a more wide-ranging version of this question to end my AI final exams many years ago, in which students had a chance to write a summary of the important ideas they had learned in the course. I'm not sure what reminded of the idea (perhaps one of James Tanton's essays), but this seemed like a nice way to give students a chance to boost their grades without a curve. I figured I would be generous and give them some latitude with their own experiences. My hope was that students could end the exam on a good note, feeling positive about something they learned and appreciated rather than solving yet another problem I fished out of fifteen weeks of material. There was a small risk -- what if a bunch of them panicked at the unusual question and couldn't think of anything to say? But that risk exists for almost any question I ask.

The question seems to have gone over quite well. Some students talked about a specific topic from the course, among them variable arity functions, currying, higher-order procedures, and syntactic abstraction. That's mostly what I had in mind when I wrote the question, even if some of their answers were covered in part somewhere else on the exam. Others answered more generally than I expected. A couple talked about how the course gave them a deeper appreciation for data abstraction; a couple of others wrote about the experience of writing an interpreter and having to live with their design decisions as the code as it grew over three weeks. All but one student wrote an answer substantive and reflective enough that I didn't even have to think about how many points to award. I was happy to read them.

I really shouldn't have been surprised. Most students care more about their learning, and get more out of a class, than exam answers and classroom participation might indicate. They face a lot of pressures, and as a result have a limited amount of time and energy to express about any one course day in and day out. But making software matters to most of them; sometimes even big ideas matter. This question let them express some of what made the class work for them.

This problem had unexpected effect... I ended the exam on a good note. I put down my grading pen feeling good about the course, knowing that each student learned something that stood out to them, that they appreciated enough to write a few sentences about. I got a small glimpse of how they changed as a result of the course. I put the question on the exam for the students' sake, but it affected me as much as it affected them.

That's not a bad way to end the semester.

Posted by Eugene Wallingford | Permalink | Categories: Teaching and Learning

May 04, 2018 1:25 PM

No Venom Here

Ken Perlin liked Ready Player One at the theater and then went off to read some reviews:

Many critics seem incensed, indignant, left sputtering in outrage at the very idea of a Spielberg film that is simply fun, a pop confection designed mainly to entertain and delight.
Perhaps some of it is their feeling of horror that modern pop culture might be something worthy of celebrating, simply for the sake of celebrating a phenomenon that many people find delightful. But why the extreme degree of venom?

I am an unashamed fan of pop culture: music, TV, movies, and all the rest. My biggest complaint these days is that I can't keep up with all the good stuff being created... (It helps that I'm not as big a fan of superhero movies as most people.) Critics can claim to serve as the gatekeepers of culture if they want, but I'll enjoy "Shut Up and Dance" [ YouTube ] all the same.

Posted by Eugene Wallingford | Permalink | Categories: General