more from Theodore Sider

Single Idea 15001

[catalogued under 5. Theory of Logic / H. Proof Systems / 4. Natural Deduction]

Full Idea

'Tonk' is stipulated by Prior to stand for a meaning that obeys the elimination and introduction rules; but there simply is no such meaning; 'tonk' cannot be interpreted so as to obey the rules.

Gist of Idea

'Tonk' is supposed to follow the elimination and introduction rules, but it can't be so interpreted


Theodore Sider (Writing the Book of the World [2011], 06.5)

Book Reference

Sider,Theodore: 'Writing the Book of the World' [OUP 2011], p.103

A Reaction

'Tonk' thus seems to present a problem for so-called 'natural' deduction, if the natural deduction consists of nothing more than obey elimination and introduction rules.