Design, Decision Making and the Halting Problem

Design is one of the most 'decision intensive' activities that humans engage in. Whether a building, appliance or artwork, the parts we see- that we have the luxury of taking for granted- are all the result of very deliberate decisions. We don't see or care about the decisions but we can feel the way it hangs together- the quality, integrity and resolution of the final outcome.

But decisions are hard...we actually go to lengths to avoid them. In a very fundamental way humans are not set up to make discreet decisions- rather, like all living things, we are designed to run programs- that is, simple pre-set stimulus and response.

Have you ever heard of the Halting Problem? From computability theory, the halting problem is the issue of determining...whether a program will finish running, or continue to run forever. Or in other words, whether the programme will conclude and arrive at a 'decision' or get caught in an endless recursive loop trying to arrive at one.

This is a theory specific to the possible development of artificial intelligence, its hard to teach computers to do a trick that we're not really sure how we do ourselves. Writer Kim Stanley Robinson explores this brilliantly in his novel Aurora. The point being that this programming problem is obviously one that humans share.

The First Problem

Whether writing, drawing, painting, or any act of creation, the first problem of design is in how to start. We call this the tyranny of the blank page. We're not talking about having the requisite skill or talent to direct the pen, rather it’s that in that moment, every choice is equally possible. Consequences flow from choices, big ones and little ones, and the narrative develops by degrees, but we can’t easily see the consequences of a choice until after it’s made. We can’t tell if they will be good choices and so we struggle to make any choice at all.

This kind of bewildering cloud of probability sits behind every decision and makes it hard for us to act with deliberation. Making decisions is difficult and exhausting and in some cases just impossible.

The fact is, human beings hardly ever act with deliberation- we simply react on habit, on instinct, on programmed pre-sets, built up on trial and error and on comfort and conformity. That's not an indictment, this actually works fine most of the time- after all it’s the way we’re engineered. Imagine if you had to choose to activate the string of individual decisions and actions required to make your heart pump, pull your hand from the stove, to walk along the street, or bring a vehicle to a stop. We don't decide, deciding is too slow- we'd never survive. Instead we build up experience from feedback that lets us free-associate and run routines that manage the detail. And in many ways we manage our day-to day lives, relationships and activities in exactly the same way, by pre-established habits and routines. As organisms we simply couldn't afford the energy required to make every decision from first principles.

But there are circumstances where deliberate decisions need to be made. A programmed response is fine within a steady state, but to create new and novel things we have to be in a position to make new and novel decisions.

As an example close to hand- the design and construction of any complex building requires literally thousands of decisions, it’s one of the ultimate blank pages. Doing it once is difficult... doing it over and over again as a career is a unique discipline.

While some aspects of construction haven't changed a great deal in the past 2000 years, the modern construction industry is highly specialised, bureaucratic, litigious and technically demanding. The functional and economic expectations attached to a building are overwhelming. Within nature, organic building processes involve evolutionary trial and error and a gradual refinement. Architectural products however are generally one-off and yet are required to be free of avoidable error. Every decision has novel consequence.

The Second Problem

The second problem of design, is how to keep on starting. Having struck a line on the page, we have to keep building line upon line, making narrative choices toward some conclusion. If it's hard to make decisions, it's equally hard to articulate how we make them, but it's worth a try. When a reader picks up a book they only see a finished item total and complete, but the book has within it structure and order and narrative elements built up in layers. Architecture is certainly the same. Ideas and decisions are layered, interlocking one on top the other, to arrive at a final product. No-one ever arrived at the whole thing perfect and complete. So the first discipline it to acknowledge that there is an order and hierarchy to making decisions, there's a process.

Buildings have a literal structure, upon which everything is layered up and hangs from. That's the order its built in. But strangely in the design of buildings, the structure only becomes obvious after the useful space has been laid out. It's a kind of chicken and egg situation. This brings us right back to the halting problem. A computer can't see beyond a decision and so can't make the decision- but people have to. To do this designers routinely employ a strategy we'll call 'lets pretend'. To work through a design problem you can't deal with too many variables at once, (imagine a thousand building elements all vibrating in an indeterminate state), you need some to be fixed. Making an arbitrary 'as if' decision allows you to test solutions and layer up more detail without actually coming to rest. Humans are quite good at holding multiple disparate beliefs at the same time. The iterative nature of design allows you to test these 'as if' solutions without getting caught in the loop- zooming in and out of small and large scale, structure and space, solid and void- the one sequentially adjusting the other until the design finally settles into clarity. A good solution has a way of seeming obvious and self evident in retrospect, as a result of this process.

It's the ability to embrace this indeterminacy, to hold several potentials in place at once, to impose a 'lets pretend' order to a problem and finally a willingness to prune, discard, shuffle and reframe the components into a meaningful structure, that is at the heart of design thinking. It's a kind of high level meta-program that lets us make decisions.

The Physical Constraints

While design, creation and invention is a discipline that can be learnt, we have to acknowledge that there is physiological mental wiring that forms real limits to how we can and do work.

In many cases design problems can't be visualised or broached within an ordered language argument based structure. So mathematicians use numbers and designers use drawings. Architects like Juhani Pallasmaa talk about the concept of the thinking hand, that is the union of hand and mind in creative work. South African architect Peter Rich has described this in his beautiful drawings and colleague Peter Richards in his book DesignThinkingDrawing. This reinforces the iterative tactile activity of exploring a problem by physical drawing. Creative work involves coopting mental systems other than just language to visualise and attack problems, before translating them back into concrete terms.

We also have to acknowledge that as humans, we actually make very few deliberate weighted decisions day-to-day, and when we do they certainly aren’t ‘rational’ decisions. We have fairly limited abilities in that regard. We can't and don't make disinterested logical decisions. Everything in human experience is coloured by emotional nuance. We run from threat and towards reward. The role of the amygdala in the brain is to do exactly that, to code incoming and outgoing information with emotional context. This is what makes decisions possible for us. Patients with damage to this part of the brain, are physically incapable of making high level decisions, they lack any initiative at all. Information lacks any meaning for them. In our case tapping into the 'feeling' of a decision isn't irrational, but an entirely necessary part of providing relevance to our ideas. A non-verbal intuition encoded from this part of the brain (or a gut feel) is essential and again the skill is in translating this back in concrete terms.

Given that our cognitive equipment is not designed for novel decision-making we have to acknowledge that there are real physical limits to the number of decisions we can make in a day. It's literally exhausting. Most designers are hollowed out by the end of the day. Add to that the emotional burden of managing other humans and their expectations, the toll on an individual is significant and has to be well managed.

Good Enough is Just Perfect

So, if we're so limited and decisions are so hard, how do we actually do anything? Well, while its true we do not have the capacity to make great decisions, what we do have is a sophisticated set of mechanisms to deal with how we feel about our decisions, after we’ve made them. And in most cases that is good enough. No decision can be perfect because of the law of unintended consequences. In most practical respects a design decision only has has to be thoughtful, precise and timely enough to maintain the momentum of the process. Most of design, is about 'good enough' decisions, that over time become 'perfect decisions' by the weight of the work we do to make them so along the way. Like a painter layering up their strokes, the picture comes clearer as you go.

Thanks if you made it all the way to the end of this article, it took me a few goes.

#architecture #designculture #designtheory

Ryan is a director of Fulton Trotter Architects in Brisbane Australia. He writes about the human cause in a corporate world, and continues the firm’s tradition of developing young architects through training and mentoring.

find us at:www.fultontrotter.com.au