Not so dusty

As any fule kno, Brownian motion is a random jiggling of small particles suspended in a fluid. The name derives from botanist Robert Brown who first observed it in pollen grains suspended in water. It appeared to be an example of perpetual motion until Einstein explained the phenomenon using kinetic theory. Basically he ascribed the motion to random fluctuations in the way that fluid molecules impinge physically on the much larger particles. 

Over two thousand years ago, Lucretius observed Brownian motion in dust particles dancing in a shaft of sunlight, using it to prove the existence of atoms.

...look where the sun

Through some dark corner pours his brightest beams,

A thousand little bodies you will see,

Mix in the rays, and there forever fight

Arrayed in mimic troops, no pause they give

But meet and part again, nor ever cease.

From this you may conjecture of the germs [atoms]

What ‘tis for ever in the mighty void

To be tossed up and down. In some degree

Such small events may illustrate great things,

And give a clue to knowledge. So ‘tis well

That you should note these bodies how they rush

In the sun’s rays, because such rushes show

What secret hidden forces lie below.

Lucretius – On the Nature of Things.

Unwelcome ideas - part VIII

An earlier post introduced one aspect of Lucretius’ poem On The Nature Of Things - the attack on priestly mediation. Another feature of the philosophy espoused by Lucretius is the idea that the universe is made of atoms - solid indivisible units of matter - quanta of matter, we might even say. This is the ancient atomic theory of matter taught, among others, by Democritus, adopted by Epicurus and later by Lucretius.

Why did the ancients attach such importance to atomic theory and how did they arrive at it? In addition to those two questions, why was atomic theory such an unwelcome idea? Well the ancient philosophers who espoused it certainly didn’t do much in the way of formal experiments as we would recognise them. They used observation, but primarily they used ancient logic.

Lucretius’ physics rested on the twin ideas that nothing can be resolved into nothing and nothing can come from nothing. 

Firstly, matter cannot be divided and divided again into infinitely small amounts as Aristotle maintained. This would mean that matter could be destroyed as an infinitely small bit of matter would be a point with no dimensions. It would be nothing.

Secondly, if matter could be created from nothing then there could be no law dictating what can turn into what. This argument rests on the idea that nothing can have no properties, so there is no way of creating A from nothing as opposed to creating B from the same nothing.There can be no law to dictate that A must be created rather than B, because as nothing has no properties, no laws apply to it.

For if from nothing things we see were made,

All things could come from all things, and no seed

Would be required. Man from the sea would rise,

The scaly fishes from the earth come forth,

Birds dart from heaven, horned beasts and herds,

And all wild animals, born here or there,

Would hold alike the forest and field.

And all things cannot be from all things made,

Because in certain things, and them alone,

The power which can create anew resides.

Why was such a philosophy so unwelcome? Why were atoms so important to the ancients? Maybe it was because this is logic and observation rising from the swamp. Atomic theory, however primitive is bound to lead to more theories of the natural world. Theories not owned by the elite, not easily manipulated to support the status quo. In these ancient theories, maybe we see the first green shoots of intellectual independence.

Unwelcome ideas - part VII

Titus Lucretius Carus (99 – 55 BC) was a Roman poet only really known to us via his long didactic poem On The Nature Of Things. We know very little about Lucretius himself beyond his poem. He was an avid disciple of Epicurus whose peaceful writings and rational philosophy he saw as a stark contrast to the bloody, uncertain and violent times in which he lived. It is even possible that he committed suicide as some passages in his poem suggest that he saw this as the only rational way to escape intolerable social and political decline. Yet two thousand years later, Lucretius’ poem is by far the most complete and comprehensive exposition of Epicurus’ philosophy available to us. It is still worth reading both as early philosophy and a fine example of ancient scientific thinking vastly superior to Aristotle’s disastrously inept ventures into physics and cosmology.

This post is concerned with only one aspect of Lucretius’ poem, its attack on the mediating role of priests, a stance borrowed directly from Epicurus. To gain some idea of why this attack was so unwelcome to established Roman ideas, we first have to understand how powerful it is.

Lucretius (or Epicurus) is saying that in our terms the gods represent the First Cause and all human life must be lived in and encompassed by secondary causes. In this sense, neither the priesthood nor anyone else is in a position to mediate between us and our gods.

Aye, you yourself some day, perhaps o’ercome

By priest’s alarming words, will fall away.

For even now how many dreams they paint

Such as the settled reasoning of your life

Might well o’erturn, and all your future fate

With terror darken. Not without due cause.

For if men knew there was a certain end

Of all their woes, it would be in their power

Priest’s threats and terrors boldly to defy:

But now there is no power to say them nay

Since after death eternal punishment

Must be the dreaded doom.

Lucretius’ antidote to these priestly terrors is to understand the natural world in terms of logic, atomic theory and observation.

Seeking the words by which, and in what verse

I may at length shed round your mind a light

Which will display to you the hidden things,

This terror then, these shadows on the mind

‘Tis not the radiant sun, nor day’s bright beams

Can them expel, but nature’s face and plan.

In other words, to know our place in the scheme of things, we must study and understand the natural world and thus rise above the spurious claims of priestly mediation. For nobody could conceivably mediate with the First Cause. The natural world is our only world and understanding it is our antidote to philosophical anxiety and our route to a personal philosophy.