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PH502

Reasoning and Logic

**This information is for the 2019/20 session.**

**Teacher responsible**

Dr Laurenz Hudetz

**Availability**

This course is available on the MPhil/PhD in Philosophy. This course is not available as an outside option.

The course is, in general, only aimed at those students who have never taken a course in formal logic before. For such students the course is compulsory.

**Course content**

Arguments and inferences play a fundamental role both in intellectual disciplines and in everyday life. For example, a scientist will test a particular theory by reasoning that if that theory is true then some other claim, one that can be checked experimentally, must be true as well. Or a politician will give an argument for a certain migration policy. More mundanely, we reason and draw inferences all the time and our actions are guided by the conclusions we draw. We are so used to this that we are often not even aware of it.

Logic is the study of arguments and inferences – it therefore has an enormously broad scope. Its main task is to give an explicit characterisation of those arguments and inferences that are valid (and hence differentiate them from those that are invalid). Logic tells you exactly when some conclusion follows from some premises and when it does not. It turns out that, in everyday life, many arguments are far from the ideal of logical validity. However, philosophers and social scientists should be able to devise arguments that satisfy this ideal.

In view of that, several questions arise:

- What exactly are arguments and inferences and which quality criteria should they satisfy?
- What exactly does it mean that the truth of a statement is guaranteed by the truth of other statements?
- What exactly does it mean that a statement is true (given an interpretation of the language in which it is formulated)?
- Is it possible to find a few manageable inference rules such that, given any valid argument, its conclusion can be derived from its premises using only these rules?
- Is there a general method for checking whether a given argument or inference is valid?

This course provides answers to these and related questions. It begins with a simple system called sentential or propositional logic, which despite its simplicity captures a significant range of important arguments. The course then focuses on predicate logic, which is much more powerful and provides the logical basis for analysing a great variety of arguments and theories.

**Teaching**

15 hours of lectures in the MT. 15 hours of lectures in the LT.

Appropriate back-up teaching will be arranged with individual students.

This course has a reading week in Week 6 of both MT and LT.

**Formative coursework**

Regular exercises will be set on the basis of the material covered in lectures.

**Indicative reading**

There will be comprehensive lecture slides and materials covering the entire course content. Textbooks whose treatment is close to that adopted in the lectures are:

Halbach, V. (2010): The Logic Manual. Oxford University Press.

Magnus, P.D. and Button, T. (2017): forallx: Cambridge. (available online)

**Assessment**

Exam (100%, duration: 3 hours, reading time: 15 minutes) in the summer exam period.

** Key facts **

Department: Philosophy, Logic and Scientific Method

Total students 2018/19: 3

Average class size 2018/19: Unavailable

Value: One Unit