1. Introduction

You will have come across the word ‘logic’ in many different contexts.

Think of the Sherlock Holmes TV programs or another good detective story. Sherlock (or another detective hero) uses logic to make sense of the tiny clues that no one else has even noticed. He uses his power of reasoning to say ‘if I can see this then such and such has probably happened’

You, also use logic every day of your life. What this really means is that you use your previous knowledge and apply a set of rules in order to make a decision Think of the following scenarios:

1. You see someone about to put their finger into a pan of boiling water what does your logic tell you to do?

Previous knowledge – boiling water is dangerous and will burn on contact.

Logical outcome – you give a warning to the person not to put their finger into boiling water.

A parent will use this kind of logic all the time as their child may not understand the rules yet e.g. ‘Don’t play with matches’, ‘Look right and left before crossing a road’.

2. You want to open your front door which is locked

Previous knowledge – locked doors can be opened with the correct key. You have that key

Logical outcome – you use the key to open the door.

General Logic

What you have done is looked at a situation, applied some rules and come to a conclusion or course of action. This is general logic. It is also called common sense and people are very good at it. Computers on the other hand cannot normally deal with 'common sense', it is far too subtle.