---
title: "How To Use What You Know"
authors:
  - "Carl Hewitt"
doi: ""
url: "https://ijcai.org/proceedings/1975/29"
pdf: "https://ijcai.org/proceedings/1975/0029.pdf"
venue: "Proceedings of the Fourth International Joint Conference on Artificial Intelligence"
year: 1975
pages: "189-197"
track: "Planning and Problem Solving"
keywords:
---

# How To Use What You Know

Carl Hewitt

*Proceedings of the Fourth International Joint Conference on Artificial Intelligence*, pages 189-197.

## Abstract

This paper surveys the state or the art In the development of problem solving mechanisms for PLANNER-like formalisms. A major design goal for such formalisms Is that "For ony •illflll ,,;,.,,. nf lmn111lt'd•" lht!rt! arll no1urol t>lacea in 1h~ /ormaliam lo ,ror.t'Ju.rnll y r.mht!d I hr. knntnlt!d•r. ao 1ho1 il 111ill htt uat!d "'""" il ia a,.rnprioltt nnli nol u.at!li "'""" il ia inappropritJit!." Although this goal is still vtry far from being achieved, considerable progress Is bting made. This paper contains no major conctptual innovations a It hough It does describe and give the rationale for many of the design decisions that have been made In PLASMA [for PLANNER-like ~stem Modeled on Actors) which is currently being implemented at M.I .T. as part of a Programming Apprentice project and for other applications. The paper tries to delineate major unsolved problems and make suggestions for how some of them may be attacked. Argument! are presented against the competing predicate logic paradigm for the Implementation of knowledge-based systems.