Socialist Worker

It was all set in motion by Isaac Newton

We continue our series on Einstein by looking at an earlier upheaval in science

Issue No. 1944

Isaac Newton

Isaac Newton

One hundred years ago Albert Einstein published four papers that began a revolution in science. There are many reasons why socialists might be interested in Einstein. He was a lifelong opponent of militarism and oppression, and he became a committed socialist.

But this doesn’t tell us why he made his scientific breakthough.

To understand Einstein’s contribution we have to look at how an earlier revolution in science created a certain picture of nature, and how that picture began to break down. What we would recognise as science was born during the massive social changes sweeping Europe in the 16th and 17th centuries. As Karl Marx’s friend and colleague, Frederick Engels, wrote, “Natural science developed in the midst of the general revolution and was itself revolutionary.”

The old order — based on a mass of peasants working in agriculture, ruled by a small elite of landowners — was dying. A new order, the earliest form of capitalism, was being born. This system was centred on towns rather than the land.

New production methods required new machinery, trade required navigation and engineering, and the wars fought to establish trade routes needed weapons and a grasp of ballistics. In short, a new scientific understanding of how the world worked was required.

It was the English scientist Isaac Newton who most rigorously developed this understanding.

Newton shared many of the views and aspirations of the emerging capitalist class. In 1687 he published his Philosophiae Naturalis Principia Mathematica. In it he set out the basic laws explaining how gravity worked and how objects move.

Many of his ideas contradicted the common sense of the time. For example, the first of Newton’s famous laws of motion states that a moving body will continue to move in a straight line, at constant speed, until a force acts on it. But this is not how we experience the world — objects generally grind to a halt after being set into motion.

Newton’s law, like all scientific laws, is an “abstraction”. Newton considered what would happen if you removed all friction and air resistance — the forces that make objects grind to a halt. In this case an object would carry on moving until a force acted on it.

Once you have abstracted away from the common sense picture of the world, you can grasp the basic law. Then you can piece together all the bits of the puzzle and explain the real motion of objects.

But Newton’s ideas did not simply challenge people’s common sense. They were also a challenge to the whole worldview of the old order.

Most previous views of nature had been based on “idealism”. They required god and religion to make sense of the natural world. But Newton’s mechanics were “materialist” — they allowed people to understand nature based on its own laws, which existed independently of god or the human mind.

It was in this sense that Engels saw the emergence of natural science as revolutionary, part of a wider battle between materialism and idealism.

There were limits to Newton’s materialism. He personally believed in god, and religious ideas crept back into Newton’s physics in two ways.

Firstly, Newton’s laws imply a kind of relativity. If bodies unaffected by a force simply carry on moving it becomes meaningless to say a body is at rest. Common sense tells us that an object sitting on the ground is at rest.

But we also know that the Earth is rotating and orbiting round the sun. Measurements such as speed or distance are relative.

Newton was unhappy with the relativity implied by his ideas and he introduced the idea of an underlying “absolute space” (and hence of absolute rest), associating this idea with god.

Secondly, Newton’s universe was based on a kind of “mechanical materialism”. His solar system is like a cosmic clockwork mechanism, the planets revolve around the sun in a timeless way. He did not ask what set the planets on their path or where they came from in the first place — this was reserved for god, and the church, not science.

Next week I will explain how Newton’s mechanical materialism began to break down, laying the basis for Einstein’s new ideas.

