Anaximander

« arise from something different' (Aristotle, Physics 204b26, A16).

As it stands, the argument is laden with Aristotelian terminology, and does not prove that the apeiron is qualitatively indefinite, only that it is different from the four Aristotelian elements.

Its authenticity has been questioned, but it probably has an Anaximandrian kernel, attackingThales ' conception of water as the basic material of the universe using the argument: 'If everything were made of, or originated from, water, then everything would be wet; but some things are wet, others dry (the opposite ofwet); therefore, the basic substance cannot be wet, or dry either' (see Thales §2 ).

The argument can be generalized to show that the basic substance is unlike any definite substance and lacks all perceptible qualities.

3 The kosmos The point of having an indeterminate originative substance is to allow to arise the wide variety of things (including opposites) that we find in the world around us.

Anaximander's account of the origin of the kosmos confirms this interpretation.

From the eternal apeiron , 'something capable of producing hot and cold' separated off. This gave rise to hot in the form of a sphere of flame, which surrounded cold, in the form of dark mist, 'like bark around a tree' .

The sphere of flame subsequently broke up to form the sun, moon and stars, while the mist afterwards became earth and sea.

This is not a creation myth where a divinity creates or acts on matter separatefrom itself, but an essentially biological account of generation or development which takes place because of thenature of the material that generates the kosmos .

On this account, the apeiron plays no active role after the obscure initial process, which is described as 'separation off' .

Once started, the world goes its own way. Anaximander speaks of other events that involve 'separation off' , and to judge by them the process does not require purposeful activity or the intervention of an agent.

It need not involve any more than some part or amountof an existing thing coming together and being isolated from the rest in such a way as to take on a distinct identityfrom the rest and behave differently.

Several details of Anaximander's astronomy deserve mention.

The heavenly bodies are rings of fire enclosed in tubes of mist pierced with holes for the fire to shine through.

Eclipses and thephases of the moon are caused when the holes are blocked.

The sun is the same size as the earth.

The sun isfarthest from the earth, followed by the moon, with the stars nearest.

The earth is a cylinder, 'like a column drum' , whose depth is one-third its breadth.

Anaximander gave the distances of the heavenly bodies from the earth, andalthough the evidence is untidy, most scholars agree that he made the distances of the stars, moon and sunrespectively nine, eighteen and twenty-seven times the size (?breadth) of the earth.

The earth is in the centre ofthe kosmos and remains there without support.

The absence of the apeiron and of the Olympian gods is notable, as is the boldness of Anaximander's ideas.

His figures for the size of the kosmos are fanciful, but his conviction that the kosmos is symmetrical and based on proportion, and the tenet that important facts about the physical world can be expressed numerically, are a priori principles worthy of a scientist.

The odd picture of the celestial bodies asrings rather than points of fire is doubtless the answer to the question where all the fire in the cosmogonic sphereof flame went to.

Anaximander may (although this is speculation) have located the stars nearest the earth throughthe following reasoning: their light is dimmest and they give the least heat because the fire they are made of is lesspure than that of the sun; celestial fire is purer the less affected it is - and therefore the more remote it is - fromthe cool region of the earth; therefore the stars are nearest the earth and the sun farthest.

Anaximander believedthe earth stays in the centre without support 'because it stays put on account of its similar distance from all things' (Hippolytus, Refutation I 6.3, A11).

Also, 'it is no more appropriate for what is located in the middle and similarly related to the extremes to move up, down or sideways; and it is impossible to move in opposite directionssimultaneously; and so by necessity it is at rest' (Aristotle, On the Heaven 295b12, A26).

Although not all scholars accept this reasoning as Anaximander's , there is no reason why he could not have said something similar to the former of these reports.

Aristotle could then have supplied the missing steps in the argument, which amounts to thefirst recorded use of the Principle of Sufficient Reason.

The picture of the earth hanging free in the middle of thekosmos contrasts with Greek mythology and with Thales' belief that the earth rests on water, as well as with that of Anaximander's successor, Anaximenes (§2) , who believed that it is supported by a column of air.

It is based on our experience that the earth does not seem to move, along with Anaximander's theory of the origin and structure of the kosmos , which leaves no room for a prop.

Like other Presocratics, Anaximander gave accounts of meteorological phenomena agreeing with his cosmogony and cosmology.

Fire and dark mist are again prominent, asis 'separation off' , this time caused by the sun's heat, which accounts for wind, clouds and (if 'separation off' of dry from wet involves 'exhalation' and 'drying' ) rain, as well as other effects, including the eventual desiccation of the earth.

Wind in turn is the cause of thunder, lightning, thunderbolts, waterspouts and hurricanes.

Anaximander tookthe same approach to the problem of the origin of life.

'The first animals were born in moisture, surrounded by thorny barks, and when they grew older they went forth onto drier regions, and when the bark broke off they liveda different life for a brief time' (Aëtius , V 19.4, A30).

Animals have a similar origin to the kosmos (the repetition of the image of a tree's bark is hardly coincidental) and one linked to the progressive drying out of the sea.

Regarding the beginning of human life, 'from water and earth that had been heated arose fishes or animals very similar to fishes; humans grew in these and remained inside until puberty; then at last they burst and men and women cameforth already able to feed themselves' (Censorinus, 4.7, A30).

Although this is not an anticipation of the theory of evolution (as some have thought), it gives a typically bold solution to the problem of how the first generation ofhumans could have survived until they could take care of themselves and reproduce.

Two other issues are whetherour kosmos will last forever and whether it is unique.

Regarding the first, Anaximander's fragment can be taken to imply that the inconclusive war between opposites will continue forever, so that our kosmos has a beginning but no end.

However, there is no trace of such a view in the sources and, since later Greek philosophers strongly rejectedsuch asymmetries, the silence indicates that Anaximander did not maintain the view explicitly.

On the other hand,since it is unclear how the kosmos would come to an end, it is likely that he did not discuss the matter in any detail.

Regarding the second issue, most scholars hold either that Anaximander considered the kosmos unique or that he posited an infinite succession of kosmoi , one after another.

However, several sources mention a limitless number of coexistent kosmoi .

The evidence is not unanimous and can be taken in different ways, but it would arguably be consistent with Anaximander's system and with his use of the Principle of Sufficient Reason for him to maintain that the process which formed our world need not occur only at one time or in one place.

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