Van Helmont's account brings us face to face with a number of riddles. Certainly, there is nothing strange to us in his describing carbon dioxide gas as being 'finer than vapour and denser than air'; but why did he call this a 'paradox'? What prevented him from ranking it side by side with air? As to air itself, why should he describe it as belonging to the realm of the 'uncreated things'? What reason was there for giving 'vapour' the rank of a particular condition of matter? And last but not least, what was the ancient conception of Chaos which led van Helmont to choose this name as an archetype for the new word he needed?
To appreciate van Helmont's astonishment and his further procedure, we must first call to mind the meaning which, in accordance with the prevailing tradition, he attached to the term Air. For van Helmont, Air was one of the four 'Elements', EARTH, WATER, AIR, and FIRE. Of these, the first two were held to constitute the realm of the 'created things', the other two that of the 'uncreated things'. A brief study of the old doctrine of the Four Elements is necessary at this point in order to understand the meaning of these concepts.
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The first systematic teaching about the four elementary constituents of nature, as they were experienced by man of old, was given by Empedocles in the fifth century B.C. It was elaborated by Aristotle. In this form it was handed down and served to guide natural observation through more than a thousand years up to the time of van Helmont. From our earlier descriptions of the changes in man's consciousness it is clear that the four terms, 'earth', 'water', 'air', 'fire', must have meant something different in former times. So 'water' did not signify merely the physical substance which modern chemistry defines by the formula H2O; nor was 'air' the mixture of gases characteristic of the earth's atmosphere. Man in those days, on account of his particular relationship with nature, was impressed in the first place by the various dynamic conditions, four in number, which he found prevailing both in his natural surroundings and in his own organism. With his elementary concepts he tried to express, therefore, the four basic conditions which he thus experienced. He saw physical substances as being carried up and down between these conditions.
At first sight some relationship seems to exist between the concept 'element' in this older sense and the modern view of the different states of material aggregation, solid, liquid, aeriform. There is, however, nothing in this modern view that would correspond to the element Fire. For heat in the sense of physical science is an immaterial energy which creates certain conditions in the three material states, but from these three to heat there is no transition corresponding to the transitions between themselves. Heat, therefore, does not rank as a fourth condition by the side of the solid, liquid and aeriform states, in the way that Fire ranks in the older conception by the side of Earth, Water and Air.
If we were to use the old terms for designating the three states of aggregation plus heat, as we know them to-day, we should say that there is a border-line dividing Fire from the three lower elements. Such a border-line existed in the older conception of the elements as well. Only its position was seen to be elsewhere - between Earth and Water on the one hand, Air and Fire on the other. This was expressed by saying that the elements below this line constituted the realm of the 'created things', those above it that of the 'uncreated things'. Another way of expressing this was by characterizing Earth and Water with the quality Cold; Air and Fire with the quality Warm. The two pairs of elements were thus seen as polar opposites of one another.
The terms 'cold' and 'warm' must also be understood to have expressed certain qualitative experiences in which there was no distinction as yet between what is purely physical and what is purely spiritual. Expressions such as 'a cold heart', 'a warm heart', to 'show someone the cold shoulder', etc., still witness to this way of experiencing the two polar qualities, cold and warm. Quite generally we can say that, wherever man experienced some process of contraction, whether physical or non-physical, he designated it by the term 'cold', and where he experienced expansion, he called it 'warm'. In this sense he felt contractedness to be the predominant characteristic of Earth and Water, expansiveness that of Air and Fire.
With the help of these qualitative concepts we are now in a position to determine more clearly still the difference between the older and the modern conceptions: in particular the difference between the aeriform condition of matter, as we conceive of it to-day, and the element Air. Contractedness manifests as material density, or the specific weight of a particular substance. We know that this characteristic of matter diminishes gradually with its transition from the solid to the liquid and aeriform states. We know also that this last state is characterized by a high degree of expansiveness, which is also the outstanding property of heat. Thus there is reason to describe also from the modern point of view the solid and liquid states as essentially 'cold', and the aeriform state as 'warm'. But aeriform matter still has density and weight, and this means that matter in this state combines the two opposing qualities. Contrary to this, Air, as the second highest element in the old sense, is characterized by the pure quality, warm. Thus, when man of old spoke of 'air', he had in mind something entirely free from material density and weight.3
By comparing in this way the older and newer conceptions of 'air', we come to realize that ancient man must have had a conception of gravity essentially different from ours. If we take gravity in the modern scientist's sense, as a 'descriptive law of behaviour', then this behaviour is designated in the older doctrine by the quality 'cold'. If, however, we look within the system of modern science for a law of behaviour that would correspond to the quality 'warm', we do so in vain. Polarity concepts are certainly not foreign to the scientific mind, as the physics of electricity and magnetism show. Yet there is no opposite pole to gravity, as there is negative opposite to positive electricity, etc.4
In the older conception, however, the gravitational behaviour 'cold' was seen to be counteracted by an autonomous anti-gravitational behaviour 'warm'. Experience still supported the conviction that as a polar opposite to the world subject to gravity, there was another world subject to levity.