Philosophy of Newtonian Mechanics#

There is an underlying dogmatism in Newtonian mechanics. Once you create a model, specify the forces and initial conditions the system’s state is known for all time. There can be other systems that interact with your model, but those systems all follow Newtonian mechanics.

There’s no room for uncertainty in Newtonian mechanics. Every change in velocity is due to a force acting on an object. The universe becomes more like clockwork in this framework. Something set the universe in motion and its has been moving ever since.

Some people claim that quantum mechanics accounts for the uncertainty in the world, but the laws of quantum mechanics are derived from Newtonian equations with an added variable for the “wave function” of a particle. It adds useful tools to analyze systems that might not have initial conditions, but it is still derived from ideas regarding cause and effect.

Cause and effect in Newton’s universe#

In the Newtonian universe, every effect is due to a cause and that cause is the result of some other effect,

Every body perseveres in its state of being at rest or of moving uniformly straight forward except insofar as it is compelled to change its state by forces impressed. - Isaac Newton, Principia

This principle has been used to describe the motion of the moon, stars, and comets. The path of the moon has been correctly predicted for the last century using Newtonian mechanics and gravitation.

Free will in Newton’s universe#

How does free will play a role in Newton’s universe?

Some philosophers try to separate physical laws from beings with free will, but this can be a slippery slope. We can point to a brain as something that makes decisions and is the cause of environmental changes, but what caused the brain to create a cause? It must have had some external stimulus to create an idea. In that sense, its a sophisticated feedback loop, but it is still subject to physical laws since it is made of physical connections.

Other philosophers might say that Newton’s universe is all there is. If we had a big enough computer, we could create and solve a universal equation of motion and see the future. In this view, everything that will happen was destined to happen based upon some initial conditions in the universe.

What do you think?#

Are humans and animals above Newton’s laws of motion? or are we trapped in a universe going through the motions of something out of our control?