Logic

With logic we are arguing on shifting ground. An ‘object’ may have a ‘property,’ and belong to some ‘genus’ of object. There are several forms that a valid verbal argument can take, such as the following:

  • X is of genus G
  • Objects of genus G have property P
  • ∴ X has property P

This is all well and good. An aim is to categorize all the different types of arguments that occur. This is of use in reasoning syllogistically, according to previously lain-out patterns, without having to consider them again as to whether they are true or not; and in distinguishing ‘logical fallacies’ in an argument that someone has used, by showing the argument is not a valid form.

We should, however, bear in mind the limits of such formalistic reasoning. For example, what is meant by an ‘object’? If we leave aside the question of whether the ground beneath our feet, and other edge cases, are to be counted as objects, and assume an object are things like cups, knives, shoes, and so on, then an object is an entity in the consciousness of an individual. It is, moreover, an entity that is or that could be shared between different individuals. Between the perception of different individuals, it seems to me that there is an ‘external reality,’ by which perception is determined, and towards which perception is continually returning. The validity of reasoning about an object assumed to exist, with a distinct individuality, is dependent upon the validity of the original discerning of it by a conscious observer. Faces may appear in smoke, and they may have conversation; but the observer who reasons about them logically will soon see the entities of his analysis dissolving into their environment, and will find his carefully cultivated theories merely weeds growing in his mind’s soil.

Details of logic

Some of the nature of perception and reasoning displays itself in natural language. The typical1 uses of the main lexical categories correspond to some of the entities that occur there:

  • Noun — Object
  • Verb — Action
  • Adjective — Property
  • Prepositional phrase — Location

This study should be motivated by examples.

There are different logics that have been considered, such as Boolean logic, whose unit is the proposition.

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