Terry Winograd’s SHRDLU. CC-BY-SA-4.0

The Illusion of Intelligence

Early AI, Rule-based systems, SHRDLU, and rational agents, and my experience coding a simple blocks world

Rational Agents

Achieving rationality is the overarching goal of artificial intelligence. This goal, to create a rational agent, is understandably hard. One of the most intimidating problems in a variety of cases is the value alignment problem, where the rational decision might not always be the best one for our situation. For example, a sophisticated enough robot could easily win chess by bribing it’s opponent or causing distraction — the challenge is to contain the algorithm’s possible solutions to the scope of the problem. We want our robot to win chess by playing chess.

Rule-based systems

Rule-based systems are exactly what they sound like. They are algorithms with hand-coded rules that the machine should follow when faced with any problem it is given.

Microworlds and SHRDLU

In the late 60’s, Marvin Minsky et al. suggested that the artificial intelligence community shift their research to working in microworlds. Since the real world included too many hidden variables for early AI to feasibly interpret, the next best thing was to create AI that could operate within restricted, digital worlds. In these digital worlds, called microworlds, researchers could focus on programming algorithms that made rational decisions in a slightly more straightforward environment.

Even fifty years later, SHRDLU is still impressive to watch in action.
Person: What does the box contain?
Person: What is the pyramid supported by?
Computer: THE BOX.
Person: How many blocks are not in the box?
Computer: FOUR OF THEM.
Person: Is at least one of them narrower than the one which i told you to pick up?
Computer: YES, THE RED CUBE.
Person: Is it supported?
Computer: YES, BY THE TABLE.

Creating a Blocks World

Despite being somewhat archaic in implementation, blocks worlds and rule-based artificial intelligence still holds important lessons on the goals of artificial intelligence, as well as the understanding of logic required for more esoteric subjects.

Hint, this NLP program was just a regular expression that searched for ‘B’ or ‘A’ in the text.



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adam dhalla

15 y old learning about machine learning, as well as a lifelong naturalist. Climate activist in Vancouver. Writer. Visit me @ adamdhalla.com