The 'birth' of science: established, historically, as having occurred around the time of Galileo and Sir Francis Bacon- (approx. beginning of the 16th century)With Galileo responsible for the idea of 'experimentation' and Bacon for the idea of a 'scientific method', science took off and progressed in a highly successful manner.

By the time of August Comte (1788-1857), roughly 200 hundred years later, science was a well established and well considered institution.

Comte endeavoured to gain a better perspective on scientific activity by looking at it's historical development. He undertook a massive survey of the development of science in various areas of research (e.g. physics, chemistry, biology).

Comte had an agenda in his research however. Specifically, he wished to promote his own ideas concerning how science should be carried out.

Comte called his position on the way science should proceed 'positivism'

According to positivism, the ultimate goal of science should not be to develop theories that explain the world. Instead the ultimate goal of science should be to find true generalizations about nature (as Bacon originally proposed).

Using history (as he saw it) to back him up, Comte said that scientific development went through three stages:

The theological stage

The metaphysical stage

The positive stage

Comte felt that the stage of an area of research that involved the creation of theories to explain observation was in fact an immature stage. He called this immature stage 'the metaphysical stage'.

According to Comte, the metaphysical stage, in which science postulates hidden objects and forces to explain nature, is really only a modification of an earlier, theological stage. Instead of resorting to gods and spirits, science in the metaphysical stage resorts to inanimate, impersonal objects and forces, but this is only a slight improvement.

'Metaphysical' entities are really just as ad hoc and imaginary as theological entities.

According to Comte, scientific disciplines would eventually 'grow out' of the metaphysical stage, and realize that:

a) Science is limited to the observableand therefore

b) Science should stick with what it is good at- observation and generalization!

(You can probably see that Comte was a big fan of Bacon and Hume)

Thus, according to Comte: Science can be descriptive and predictive but never explanatory!

A great many philosophers were persuaded and influenced by Comte:

Mill (of Mill's Methods fame, among other things) thought Comte's theory was very convincing, and considered himself to be a positivistOthers, like the physicist/philosopher Ernst Mach and the conventionalists Poincare and Duhem were motivated by Comte to develop their own theories regarding the role of theory and observation in science.

(Although, interestingly, while many philosophers were convinced by Comte, this did not seem to have as much influence on scientific behaviour as it might have...)

The most direct successors of Comte were the logical positivists. They took the main part of their name and the basis of their philosophy from Comte, but felt that they were improving and adding on to his ideas.

(Thus the addition of the 'logical', to distinguish them from Comte's (presumably less logical?) positivism).

The logical positivists were philosophers of science but they were also, like many philosophers of the early 19th century, very interested in philosophy of language.

As a result, they took a somewhat novel and 'linguistic oriented' approach to the issue of theories and theoretical entities.

Instead of asking "Do theoretical entities really exist?' The logical positivists asked: "What do theoretical terms mean? For example, what is the meaning of the word 'electron'"?

Lets pause for a moment to appreciate this somewhat subtle move taken by the logical positivists.

Whereas before, people wanted to discuss the existence of the entities themselves (dealing in an area of philosophy known as ontology) now people were discussing language and meaning.

This allowed the logical positivists access to a whole new 'bag of philosophical tricks', which had been developed by philosophers of language.

Getting rid of bad rubbish...

The Logical Positivists wanted to find a way to get rid of the 'metaphysics' they felt was infesting the science of the time (early to mid 1900's).

Unlike Comte, however, they did not advocate the wholesale removal of theories from science. Instead, they tried to find ways to precisely ground theories in observation.

As staunch empiricists, the Logical positivists believed in the attainment of knowledge only through the senses. They extended this to knowledge of the meaning of words.

According to the logical positivists:

Our understanding of a meaning of a word like 'red' is gained through the experience of red objects. If I am born blind, the word 'red' is necessarily meaningless to me.

Based on this, the logical positivists said that, if theoretical statements are to have meanings, these meanings must be rooted in knowledge gained through the senses.

At this point it must be stated that the logical positivists were not the first to take such a linguistic approach. Hume (of Induction Problem fame) also pursued this line of reasoning.

According to Hume, words have meanings because they are somehow 'attached' to ideas in our heads. If a word is not attached to an idea in our head, then it has no meaning.

Therefore, the word 'ball' is meaningful because I have a ball idea in my head.

The word 'ball' is associated with this ball idea, and that gives 'ball' its meaning.

Since, according to Hume, ideas only end up in our heads via experience only words associated with experiences can have meaning. Consequently words like 'force of gravity' and electron (not to mention causation!) have no meaning.

Words like 'ball', on the other hand, are meaningful because, presumably I have experienced a ball at some time in my life and consequently have the idea 'BALL' in my head.

Fortunately, Hume's meaning argument is not as airtight as some of his other arguments.

As philosophers of language are quick to point out, the whole idea of the meaning being strictly attached to individual words is quite problematic.

Why? (From someone who has not taken another philosophy class dealing with this

problem...)

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If meaning were derived solely based on the ideas 'attached' to words, rearranging the words shouldn't make any difference to the meaning of a sentence:

Tyler tripped over Simone

should have the same meaning as

Simone tripped over Tyler.

Clearly there is more to meaning than Hume supposed.

The issue of meaning is a major topic in philosophy of language.

Suffice it to say for now that, by the time the logical positivists had arrived on the scene, people were more comfortable with meaning being associated (in some way) with statements, rather than with individual words.

Consequently, the logical positivists decided that any meaning associated with theoretical terms should be sentential in nature.

The logical positivists also weren't comfortable with Hume's use of ideas (it seems a bit surprising that Hume was, given his strict empiricist beliefs). They wanted meaning to be based on something more tangible.

Using these two criteria, the logical positivists came up with the verification principle of meaning. This principle states that:

The meaning of any statement is its method of verificationWhat does this mean? It means that you can figure out what a statement means by figuring out how you would test the truth value of that statement.

An example of verificationism

So, consider the statement:

My blue ball bounces.

How can I verify the meaning of this statement? I can verify the truth of this statement by bouncing my blue ball on the floor.

If the ball hits the floor and then flies up back off the floor, the statement is true, if it doesn't, the statement is false.

Therefore, the meaning of the statement "My blue ball bounces" is just "If I drop this blue ball on the floor, it will rebound back upwards once it has hit the floor"

Does this help with theoretical statements?

Yes!

We can simply take the meaning of any statement using theoretical terms to be the observational statements that are used to indirectly support the truth of that statement.

Thus the statement:

This coca cola is acidic

actually means

If I put a piece of litmus paper in the coca cola it will turn red.

By repeating this process with every theoretical term, science can be

successfully grounded in observation. Any terms which cannot be successfully

grounded in observation should be considered meaningless!

The logical positivists position seems to have a lot of merit:

Most people would agree that we would like our theoretical terms to have

meaning.

Since science makes use of theories to explain the observable world, and since theories are verified, indirectly, by observation, it makes sense to look to observable tests when seeking meaning for theoretical terms.

Given this, it is perhaps not surprising that Logical Positivism was a highly successful theory. In fact, it was the dominate theory in philosophy of science for over 30 years.

Much effort was put into making logical positivism a consistent and comprehensive philosophical position and it was relevant to many areas in philosophy outside of the realism-antirealism debateIt is also worth noting that Logical Positivism is generally viewed as a 'pro-science' philosophy, since it allowed scientific terms to have meaning while suggesting that much of philosophy was meaningless.

Of course, as you may have noticed by now, philosophy is not usually content to rest on its laurels, and if a criticism can be found, it will be found...

There were two main areas where Logical Positivism came under fire. Both were related to the distinction made by the logical positivists between observational and theoretical statements. The problems might be described as:

Problem of the Verification of Observational Terms

Problem of Establishing a connection between Observation and Theory

These probably sound familiar to you- they are problems that we initially brought up in connection with conventionalism.

How did the logical positivists deal with them?

Problem of the Verification of Observational Terms

The logical positivists were well aware that there were problems with the idea of observation- for example, the problem that observational statements could be mistakenly construed as being true when they were false.

The logical positivists tried to avoid this by taking up Ernst Mach's philosophy of phenomenalism (also called sensationism)

According to Mach, we never directly experience the world around us. Instead, for us, the world is effectively composed of sensations (which provide scientists with sense data).

Phenomenalism says:

Whatever the world may actually be like, apparent objects like chairs and apples are really only sensations. Chairs and apples, as such, do not exist in the world.

Anything we can actually know about the world, itself, must be inferred, indirectly, from our sensations (which may or may not be caused, somehow, by the world)

And yet- Mach did think that science needed theories in order to function. He took a conventionalist line towards theories, saying that they were useful in helping us cope with our sense data.

The logical positivists were attracted by phenomenalism, because they felt it could provide a firm foundation for verificationism.

After all, while observations may be mistaken, it is hard to dispute sensations.

When I make a statement about a sensation I am not trying to make a true statement about the world itself. I am merely trying to make a true statement about my experience of the world.

Thus, you might find any number of ways to disagree with me when I say that my chair is red, but it would by much harder for you to dispute my statement that to me the chair appears red.

Unfortunately, in attempting to construct a method of discourse that only made reference to sense data, the logical positivists ran into a serious snag.

Can you guess what this might have been?

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The logical positivists ran into two related problems when trying to base science on sense data:

Sensations are inherently private. Only I have access to my sensations. This makes it very difficult to make generalizations in science. All we can really say is "This is the way it appeared to me!" alternatively.

It seems that there would have to be as many sense-data vocabularies as there are people. Everyone would need a unique language to describe their own, unique sense experiences.

Although these problems might seem obvious to us now, the logical positivists put a great deal of effort into making phenomenalism work before reluctantly abandoning it.

Rudolph Carnap, for example, wrote an entire book dedicated to providing the foundation for a science based on sense data (The Logical Structure of the World, 1928).

Unfortunately for Carnap, after the publication of his book he realized that there were too many difficulties inherent in the phenomenalist approach and abandoned it.

With the rejection of phenomenalism, the logical positivists were forced to fall back on a more common sense notion of observation and objects.

They concluded that anything our common, everyday language denotes as a physical object (for example, chair, cat, hairbrush) should count as an observable object for science (this viewpoint is referred to as physicalism).

This was quite a disappointing compromise for the logical positivists :(The next problem of logical positivism: Observation and Theory

Even granting that logical positivism can get by using physicalism, there is still another serious issue it must deal with- the problem of establishing a connection between observation and theory.

On the face of it this seems to be a strength, rather than a problem with logical positivism. According to logical positivism, the meaning of theoretical statements simply is an observational statement.

Unfortunately, as elegant as this approach seems, it is not as straightforward in application as the logical positivists had hoped it would be.