⁂ Concepts · Cause · No. 31
Space

Thirty-eight microseconds a day, designed for before launch.

Space

The extension in which things are located - and whether it is a container, a set of relations, or a form of experience.

Theme
Cause, time and change
Tradition
Cross-tradition
Term
χώρα · chōra
Term fixed
1716

In plain terms

Is space a thing, or a way of talking about how things are arranged?

On the first view it is a container that would still be there if everything in it vanished - positions exist independently of anything occupying them. On the second there are only objects and their relations, and space is what we call the pattern of those relations. Empty space, on this account, is not a place with nothing in it. It is nothing.

Leibniz's argument for the second is elegant: if space were absolute, God could have placed the entire universe three metres to the left, and nothing whatever would be different - so the supposed difference is no difference at all.

Newton's reply was to point at rotation, which produces effects that relative motion alone does not explain.

As a philosopher would put it

Newton's absolute space is real, uniform and independent of bodies, and his bucket argument holds that the surface of rotating water becomes concave whether or not anything else exists to rotate relative to - so acceleration is absolute even if position is not.

Leibniz's relationism treats space as the order of coexistences, and the principles of sufficient reason and the identity of indiscernibles do the work: a uniform shift of everything would be a difference with no reason and no discernible consequence, so it is not a difference at all.

Kant's response is neither. Space is a pure form of outer intuition, contributed by the subject rather than found in things, which explains how geometry can be both a priori and applicable - and makes the question of what space is like independently of experience unanswerable.

General relativity reshapes the debate entirely: spacetime is dynamical, curved by mass-energy and acting back on it, which is not what either eighteenth-century party had in mind.

Where you meet it

A GPS satellite carries an atomic clock, and the system does not work unless that clock is corrected for two relativistic effects that pull in opposite directions.

Special relativity slows the satellite's clock relative to the ground because it is moving at about fourteen thousand kilometres an hour: roughly seven microseconds a day. General relativity speeds it up because it sits higher in the earth's gravitational field, where time runs faster: roughly forty-five microseconds a day. The net is about thirty-eight microseconds per day, and the onboard oscillators are deliberately offset before launch to compensate.

Uncorrected, positional errors would accumulate at around ten kilometres a day.

What this demonstrates is that space and time are not a fixed stage. The rate at which a clock runs depends on where it is and how it is moving, and a navigation system used by billions of devices works only because that is designed for - which settles a question the eighteenth century could only argue about.

What is actually disputed

Whether space is substantival or relational.

The modern form of the dispute concerns the metric field of general relativity. Substantivalists read spacetime as an entity with its own properties, which the theory appears to treat as a dynamical object with energy and degrees of freedom. Relationists read it as encoding relations between material events, and point to the hole argument - that substantivalism implies physically indistinguishable but distinct arrangements, which is exactly Leibniz's objection in modern dress.

Neither reading is forced by the physics, which is why the argument survives.

And Kant's position remains a live third option in a modified form. If the structure of space is contributed by the knower, the question of what space is independently of any observer is not merely unanswered but malformed - a claim general relativity does not obviously refute, since it describes measurable relations rather than an observer-free thing.

Commonly confused with

  • outer space The astronomical sense is a region. The philosophical question is about what extension itself is.
  • the container picture That is one answer among several, and the one relationists have been arguing against since 1716.

Defined against

  • Time The pair was treated as two independent frameworks for two thousand years and turned out to be one thing, which is among the most consequential corrections in the history of the subject

Philosophers

Works

Schools

Related concepts

Time c. 397 · Change c. 500 BC · Nature c. 330 BC · Infinity c. 570 BC · Substance c. 330 BC

The Newton-Leibniz correspondence of 1715 to 1716, conducted through Samuel Clarke, sets the terms: absolute space existing independently against space as nothing but the order of coexisting things.