Superphysics Superphysics
Section 1

The Infinite Divisibility of Our Ideas of Space and Time

by David Hume Icon
5 minutes  • 891 words
Table of contents

The Limitation of the Mind Limits our Cognition of the Existence of Objects

Philosophers often greedily embrace whatever is paradoxical.

  • They think that this would show the superiority of their science which could discover opinions so different from ordinary conception.

On the other hand, any proposal that causes surprise and admiration satisfies the mind for that very suprise and admiration, even if it is entirely baseless.

  • This creates the mutual complaisance between philosophers and their disciples.

The philosophers furnish many strange and unaccountable opinions.

  • Their disciples then so readily believe them.

The most obvious example of this mutual complaisance is in the doctrine of infinite divisibility.

I shall examine this with the ideas of space and time.

The mind’s capacity is limited and can never fully conceive infinity. Obviously:

  • whatever can be divided to infinity, must consist of an infinite number of parts, and
  • it is impossible to limit the number of parts, without limiting the division.

Our idea of any finite quality is not infinitely divisible.

By proper distinctions and separations, we can divide this idea into parts which are perfectly simple and indivisible.

We reject the mind’s infinite capacity. *

*Superphysics Note: We assume that Hume is bashing the infinite divisibility of space by Descartes-Spinoza since he bashes both in another Section

Instead, we suppose that the mind can reach the final division of its ideas.*

*Superphysics Note: This is now Planck length and Planck time which are not derived experimentally, but from derivation from known constants

Therefore, the imagination may reach a minimum idea which it cannot further subdivide or reduce without destroying.

When you tell me of the 1/1,000th and 1/10,000th part of a grain of sand, I have a distinct idea of:

  • these numbers, and
  • their different proportions.

But the images that I create in my mind to represent the sand themselves, are:

  • not different from each other, and
  • not inferior to that image of a grain of sand itself.

What consists of parts is distinguishable into those parts.

  • What is distinguishable is separable.

But the idea of a grain of sand* is:

  • not distinguishable, and
  • not separable into 20, much less into 1,000, 10,000, or an infinite number of different ideas.

*Superphysics Note: Here, Hume is mixed up between the idea of a grain of sand and a physical grain of sand. A grain of sand is divisible into atoms. So clearly, he means the metaphysical idea of a grain of sand.

The same is true for the impressions of the senses and the imagination.

Put a spot of ink on paper, fix your eye on that spot, and walk away that finally you lose sight of it. The moment before it vanished, the image or impression was perfectly indivisible. The smallest parts of distant bodies do not convey any sensible impression, not because of the lack of light striking our eyes.*

*Superphysics Note: Here, Hume makes it clear that the basis divisibilty is the physical detection capability.

It is because they are removed beyond that distance, at which their impressions were:

  • reduced to a minimum, and
  • incapable of any further reduction*.

*Superphysics Note: No, they can be further reduced or divided, but it would not be detectable anymore.

A microscope or telescope, which renders them visible, does not produce any new rays of light.

It only spreads the rays which always flowed from them.

By that means, it:

  • gives parts to impressions, which to the naked eye appear simple and uncompounded, and
  • advances to a minimum, what was formerly imperceptible.

We may hence discover the error of the common opinion:

  • that the mind’s capacity is limited on both sides, and
  • that it is impossible for the imagination to create an adequate idea of what goes beyond a certain size.

There are ideas and images perfectly simple and indivisible.

Therefore, nothing can be smaller, than:

  • some ideas which we form in the fancy, and
  • some images which appear to the senses.

The only defect of our senses is that they:

  • give us disproportional images of things, and
  • represent as minute and uncompounded what is really great and composed of so many parts.

We are not sensible of this mistake.

We take the impressions of those minute objects to be equal to the objects.

We find by reason that there are other objects vastly more minute.*

*Superphysics Note: This is because the aether naturally can go beyond physical limitations.\

We too hastily conclude that these more minute objects are inferior to any idea of our imagination or impression of our senses.

We can create ideas no greater than the smallest atom of the animal spirits* of an insect 1,000 times smaller than a mite.

*Superphysics Note: Here, Hume misunderstands Descartes’ animal spirits and is why we assume that this section attacks Descartes.

We should rather conclude, that the difficulty lies in enlarging our conceptions to create a just notion of a mite or an insect 1,000 times smaller than a mite.

To form a just notion of these animals, we must have a distinct idea representing every part of them.

According to the system of infinite divisibility, this idea is:

  • utterly impossible*, and
  • extremely difficult because of the vast number and multiplicity of these parts.

*Superphysics Note: No, we do not need to have an idea of every tiny part. We only need what is relevant.

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