Lecture #13 - Philosophy 12A Lecture #13 3/2/10 Natural...

Info iconThis preview shows pages 1–2. Sign up to view the full content.

View Full Document Right Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: Philosophy 12A Lecture #13 3/2/10 Natural deductions are the most challenging topic of the course Deciding formal validity Truth vs. Proof We will prove sequents The following is a valid LSL argument form: A & B C & D ( A & ) D ! H B H Only seven steps required for natural deduction corresponding to the argument 1) A&B Premise 2) C&D Premise 3) (A&D) H Premise 4) A 1 & E 5) D 2 & E 6) A&D 4, 5 & I 7) H 3, 6 E Rule of Assumptions: Premises of an argument are listed at the start of a proof in the order of which they are given, labeled Premise on right and numbered with its own line number on the left J (j) p Premise Rule of & Elimination: if a conjunction p & q occurs at line j, then at any later line k, you may infer either conjunct labeling the line j & E, and writing on the left all numbers that appear on the left of line j. A1,,An (j) p&q (j) p&q A1,,An (k) p j&E (k) q j&E Rule of & Introduction: For any p and q, if p occurs at line j and q occurs at line k then the...
View Full Document

This note was uploaded on 04/20/2010 for the course PHIL 63170 taught by Professor Fitelson during the Spring '10 term at University of California, Berkeley.

Page1 / 2

Lecture #13 - Philosophy 12A Lecture #13 3/2/10 Natural...

This preview shows document pages 1 - 2. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online