Recipes, Beyond Computational Procedures

Abstract

The automation of many repetitive or dangerous human activities yields numerous advantages. In order to automate a physical task that requires a finite series of sequential steps, the translation of those steps in terms of a computational procedure is often required. Even apparently menial tasks like following a cooking recipe may involve complex operations that can’t be perfectly described in formal terms. Recently, several studies have explored the possibility to model cooking recipes as a computational procedure based on a set of instructions. This vision is the foundation for the construction of robotics kitchen, as Moley. These kitchen robots have shown promising results. Moley, for instance, is the very first example of a new generation of bioinspired robotics, based on the reproduction of particular movement, cooking, through artificial arms and hands. It is entirely different from the current appliances present in our domestic domain because Moley is able to manipulate ingredients and interact with kitchen equipment in order to prepare a dish autonomously. Nonetheless, they have also shown several limitations. In particular, Moley is an entirely autonomous robot in a structured environment in which it knows precisely the object position and manipulates the ingredients based on a list of instructions and a training phase made by Machine Learning. In this contribution we contend that these limitations arise from an essential mismatch between computational procedures, as originally described by Turing in his seminal 1936 paper, and recipes. Computational procedures have been originally created to observe and modify formal symbols with formal operators. Thus, they are independent from time and they are ideally executed in a closed environment, in which the computer directly produces all the relevant changes required to produce the intended result. Recipes, instead, are followed in an open environment, in which, while time goes by, changes happen independently from the cook’s intervention: the cook puts the butter on the pan, starts the fire and then waits until the butter is melted. To operate effectively in the open environment a kitchen robot must couple computational procedures with sensors, e.g a sensor which provides a time signal. These sensors are de facto oracles for the procedures and yet are required to bridge the gap from the formal to the physical world.