The Nature and Necessity of Scientific Revolutions

What are scientific revolutions, and what is their function in scientific development?

Why should a change of paradigm be called a revolution?

Political revolutions are inaugurated by a growing sense which is often restricted to a political community which have been neglected by existing institutions.

Similarly, scientific revolutions are inaugurated by a growing sense from a narrow subdivision of the scientific community, that an existing paradigm could not explain an aspect of nature like it could before.

In both the sense of malfunction that can lead to crisis is prerequisite to revolution.

Scientific revolutions seem revolutionary only to those whose paradigms are affected by them.

To outsiders they may, like the Balkan revolutions of the early twentieth century, seem normal parts of the developmental process.

This parallel between political and scientific development is beyond doubt.

Political revolutions aim to change political institutions.

Their success therefore necessitates the partial relinquishment of one institution in favor of another.

Initially crisis alone attenuates political institutions.

• More people become increasingly estranged from political life
• Many of them commit to some reconstruction of society in a new institutional framework.

The society is then divided into competing camps.

The resulting circularity does not make the arguments wrong or even ineffectual.

The man who premises a paradigm can show what the new scientific practice will be like.

Does paradigm rejection illuminate more than human credulity and confusion?

Are there intrinsic reasons why the assimilation of a new sort of phenomenon or a new scientific theory must demand the rejection of an older paradigm?

New sorts of phenomena would simply show an order in nature not seen before.

New knowledge would then replace ignorance.

Building on Past Foundations

Of course, science might have developed in that fully cumulative manner.

Many people have believed that it did so.

Most still suppose that cumulation is the ideal.

Normal research is cumulative. It owes its success to the ability of scientists regularly to select problems that can be solved with conceptual and instrumental techniques close to those already in existence.

The same argument applies even more clearly to the invention of new theories.

There are only 3 types of phenomena about which a new theory might be developed.

1. Those already well explained by existing paradigms

2. Those whose nature is indicated by existing paradigms but whose details can be understood only through further theory articulation.

3. The anomalies

This type alone gives rise to new theories.

But if new theories are called forth to resolve anomalies then the successful new theory must somewhere permit predictions that are different from those derived from its predecessor.

And only after it had been part of science for some time could it come to seem a theory of a logically higher type, one not in conflict with its predecessors.

A century ago there was no need for revolutions. But today, this cannot be maintained because of the contemporary interpretation of the nature is accepted.

The strongest case for this restricted scientific theory is from Einstein vs Newton.

These two theories are fundamentally incompatible.

Relativity cannot show that Newtonian dynamics is wrong because Newtonian dynamics still works with most engineers.

Einstein’s theory can be used to show that predictions from Newton’s equations will be as good.

But, the objection continues, no theory can possibly conflict with one of its special cases.

If Einsteinian science seems to make Newtonian dynamics wrong, that is only because some Newtonians were so incautious as to claim that Newtonian theory yielded entirely precise results or that it was valid at very high relative velocities.

Some variant of this argument can make any theory immune to attack.

The much-maligned phlogiston theory, for example, gave order to a large number of physical and chemical phenomena.

If these were the only phenomena that the phlogiston theorists had claimed for their theory, that theory could never have been challenged.

By now that point too is virtually a tautology.

Without commitment to a paradigm there could be no normal science.

A scientist who only sticks to existing applications, gets no surprises, anomalies, or crises. [e.g. Newtonians]

But these are just the signposts that point the way to extraordinary science.

If positivistic restrictions on a theory are taken literally, then the scientific mechanism ceases to function.

Is it really any wonder that the price of significant scientific advance is a commitment that runs the risk of being wrong?

Can Newtonian dynamics really be derived from relativistic dynamics?

What would such a derivation look like?

This need to change the meaning of established concepts is central to the revolutionary impact of Einstein’s theory.

Einstein’s conceptual transformation destroys Newton’s paradigm.

It is a prototype for revolutionary reorientations in the sciences.

An out-of date theory can always be viewed as a special case of its up-to-date successor, it must be transformed for the purpose.

And the transformation is one that can be undertaken only with the advantages of hindsight, the explicit guidance of the more recent theory.

Assume that the differences between successive paradigms are both necessary and irreconcilable.

Can we then say more explicitly what sorts of differences these are?

Successive paradigms tell us different things about the population of the universe and about that population’s behavior.

Paradigms are the source of the methods, problem-field, and standards of solution accepted by any mature scientific community at any given time.

As a result, the reception of a new paradigm often necessitates a redefinition of the corresponding science.

The normal-scientific tradition that emerges from a scientific revolution is incompatible and often actually incommensurable with that which has gone before.

The impact of Newton’s work provides a striking example of these subtler effects of paradigm shift.

He rejectd Aristotle.

In an earlier period, occult qualities had been an integral part of productive scientific work.

The resulting change in the standards and problem-field of physical science was once again consequential.

By the 1740’s, for example, electricians could speak of the attractive “virtue” of the electric fluid without thereby inviting the ridicule that had greeted Molière’s doctor a century before.

Changes in the standards governing permissible problems, concepts, and explanations can transform a science.

I give 2 briefer illustrations.

1. Lavoisier

Before the chemical revolution, the phlogiston explained why some substances are acidic, others metalline, combustible, etc.

Lavoisier’s reform, however, ultimately did away with these.

2. Maxwell

Maxwell believed that light waves must be propagated through a material aether.

But he gave no account at all of how the aether could support light waves.