What exactly did A.J Ayer Mean by his term "logical construction"?

Question

In A.J Ayers' book Language, Truth and Logic, he used the term "logical construction" What is a simple definition of this term as he used it? It is described in his book on page 63.

Answer 1

I can't look at the EXACT section you're describing, because different versions often get numbered and arranged slightly differently. But throughout the text he generally refers to logic in a pretty normal way: logic is a system of reasoning that follows certain rules. Because logic is a system, any particular sample of logic it's logic itself, it's a product of logic - a logical construct.

Where Ayer veers off from how many people think of samples of logic is his observation of its all-too-common use. I think this is best illustrated with an old joke:

Three philosophers are travelling by train and looking out the windows at the passing scenery. The first nudges his fellows and says, "Look at that! A black sheep! I didn't know they had those in this part of the country!" His first companion sneers, "Perhaps they don't. All we know is that there is ONE sheep here." The third thinks for a bit, and counters, "Actually, all we really know is that the half we can see it black... the other side may be any colour at all!"

All of which is part of Ayer's point. When you think of a material object, you associate a variety of sensory impressions with it: your computer may be white, hum softly while its on, feel hard, metallic, and cold when you touch it, and so on.

He points out that all you REALLY know is that you are etting a bunch of sensory impressions (you're only seeing one side of the sheep). The only way to take these different impressions and associate them with one thing that causes all these impressions is through logic - your sensory information coincides in a particular way, so it's logical to assume that they have something to do with each other. Most people will take the construct even further and associate past sensory impressions with it and related but different impressions (so you assume that you know what the other side of the sheep looks like).

This logical construct, however, may be completely false. You may be wrong about the colour, and you may be wrong even that all your impressions have to do with the same thing. This assertion is much like Goodman's Riddle of Induction: You may discover tomorrow that there are different kinds of hard objects, and that your computer is the kind that suddenly turns soft at random times.

And because your logical constructs - your ideas about everything in the world except your sensory impressions - may all turn out to be wrong, you can really assert positively very, very little.

At least, that's what HE thinks.

Answer 2

Ayer is perhaps best known for his verification principle, as presented in Language, Truth, and Logic (1936), according to which a sentence is meaningful only if it has verifiable empirical import, otherwise it was either "analytical" if tautologous or "metaphysical" (i.e. meaningless) if neither empirical nor analytical. He started work on the book at the age of 23[citation needed] and it was published when he was 26. Ayer's philosophical ideas were deeply influenced by those of the Vienna Circle and David Hume. His clear, vibrant and polemical exposition of them makes Language, Truth and Logic essential reading on the tenets of logical positivism -- the book is regarded as a classic of 20th century analytic philosophy, and is widely read in philosophy courses around the world.

http://www.wikipedia.org/wiki/Alfred_Ayer