ABSTRACT

The subject in the major premise (or proposition) becomes the predicate in the minor premise and the conclusion is necessary, or compelled. There is no other conclusion possible in that form of reasoning. However, this form of reasoning leaves no space for examining the truth or otherwise of the premises, and is of limited use within legal reasoning for this very reason. Indeed, a logician would not be concerned about the verifiability of the premises only the purity of the form. So, an argument could be logically valid without being correct; that is, the premises could be mistaken but the form may be correct and lead therefore to the conclusion. Figure 7.8: demonstration of deductive reasoning

Deductive reasoning

Main proposition: To steal is to act contrary to s 1 of the Theft Act 1978

Minor proposition: Anna has stolen a book

Conclusion: Anna has acted contrary to s 1 of the Theft Act 1978

1 As can be seen the MAIN proposition is a general comment that to steal is to act contrary to the law.