Modern mechanism
Clear distinction must be made between purely scientific atomism — termed Chemical Atomism
And metaphysical atomism — termed Philosophical Atomism
or more simply Mechanism.
Chemical Atomism
In chemistry we distinguish two kinds of bodies — simple bodies, and compound bodies which result from the combination of the former according to invariable laws of weight and volume.
Simple Bodies — According to modern chemistry, elementary substances are composed of atoms, that is, of extremely minute particles of matter that are said to be incapable of real division by any known chemical agent* and yet possess the properties of the sensible body of which they are the smallest possible representatives.
These atoms are seldom found to exist in isolation. They have a tendency to form intensely compact little groups of two, or four, or sometimes even of a great number of atoms. These groups which ordinary physical agencies can only dissolve with great difficulty, are called ‘Chemical Molecules of a Body’.
These chemical molecules themselves unite to form more complex wholes, called ‘physical molecules’. It is by the union of these latter that the body which is imperceptible by the senses is finally built up.
Compound Bodies — As the word implies, every compound results from the combination of several simple bodies, and therefore the chemical molecules composing it must contain several atoms specifically different from one another. The name ‘Chemical Molecule of the Compound’ is given to the smallest quantity of this body that is capable of enjoying isolated existence. For example: NaCl.
As in the case of simple bodies, these molecules unite to form more complex physical molecules the resultant of which is the body as we see it.
This is a bare outline of the hypothesis of the atomic constitution of matter.
In accordance with this hypothesis chemistry describes in detail the physical and chemical properties of the combining elements, the resultant compound, the phenomena which accompany the chemical combination and the laws which govern the natural transformation of bodies.
The chemist describes each compound by a molecular formula that indicates what are the simple elements that have united to form the compound, and the number of atoms of each element contained in a chemical molecule; e.g. CO2.
Moreover by a structural formula he indicates the play of the atomic activities which results in the formation of the new compound.
The atomic theory described here belongs exclusively to the province of natural sciences.
Unconcerned with any opinions either about the nature
of simple bodies and their properties, or about the substantial essence
of the molecule of the compound, it leaves the field open to philosophical
speculations which transcend empirical date.
Philosophic Atomism or Modern Mechanism
This system is the philosophic interpretation of chemical atomism. Its leading tenets may be expressed in the following propositions:
This is more or less the theory adopted by the majority of modern scientists, either unemphatically or emphatically. But there have been movements that tend to ebb and flow around a form of neo-Mechanism, sometimes termed Energism. The neo-Mechanists are less dogmatic; instead of laying down categorically that all properties of matter are only local motion, they are content with saying that the reduction of all properties to motion ought to be the aim of all scientific explanation, and that this end will perhaps be attained by the science of the future.
They admit however that such an explanation is faced with grave difficulties, if indeed it does not lead to real contradictions.
Neo-Mechanists also refuse to pass judgement as to the real nature of things, on the grounds that it is not the province of science to solve metaphysical problems.
But as a matter of fact these differences are largely incidental, for in both systems, the only accidental reality which is taken into account is local motion; it is the sole agent admitted, whether definitely or tentatively, to explain the entire order of material phenomena.
With regard to the substance of bodies, although neo-Mechanists are unwilling either to define or even to admit it, it remains true that logically this substance must be homogeneous; since if all properties are reducible to motion and are therefore homogeneous, it is arbitrary to introduce qualitative distinctions between substances which support these different properties.
The theory of energetics (energism) is a reaction from Mechanism, a new form of dynamism.