Aggregative morphogeneses occur progressively in inorganic systems as the temperature is reduced: as a plasma cools, subatomic particles aggregate into atoms; at lower temperatures, atoms aggregate into molecules; then molecules condense into liquids; and finally liquids crystallize.
In the plasma state, hydrogen atoms split up into electrons and naked atomic nuclei. The nuclei can be regarded as the morphogenetic germs of atoms; they are associated with the atomic morphogenetic fields, which contain the virtual orbitals of electrons. In one sense these orbitals do not exist, but in another sense they have a reality that is revealed in the cooling plasma as they are actualized by the capture of electrons.
Electrons that have been captured within atomic orbitals may be displaced from them again through the influence of external energy, or by entering a virtual orbital of lower potential energy. In the latter case, they lose a discrete quantum of energy that is radiated as a photon. In atoms with many electrons, each orbital can contain only two electrons (with opposing spins); thus in a cooling plasma, the virtual orbitals with the lowest potential energies fill up with electrons first, then the orbitals with the next lowest energies, and so on until the complete atomic form has been actualized around the morphogenetic germ of the nucleus.
Atoms are in turn the morphogenetic germs of molecules, and small molecules the germs of larger molecules. Chemical reactions involve either the aggregation of atoms and molecules into larger molecules— for example in the formation of polymers—or the fragmentation of molecules into smaller ones, or into atoms and ions, which may then aggregate with others, for example in combustion: under the influence of external energy, molecules fragment into atoms and ions that then combine with those of oxygen to form small, simple molecules like H2O and CO2. These chemical changes involve the actualization of virtual forms associated with the atoms or molecules that act as morphogenetic germs.
The idea that molecules have virtual forms before they are actualized is illustrated by the familiar fact that entirely new compounds can first be “designed” on the basis of empirically determined principles of chemical combination and then actually synthesized by organic chemists. These laboratory syntheses are carried out step by step; in each step a particular molecular form serves as the morphogenetic germ for the next virtual form to be synthesized, ending up with the form of the entirely new molecule.
If it seems rather artificial to think of chemical reactions as morphogenetic processes, it should be remembered that much of the effect of catalysts, both inorganic and organic, depends on their morphology. For example, enzymes, the specific catalysts of the numerous reactions of biochemistry, provide surfaces, grooves, notches, or basins into which the reacting molecules fit with a specificity that is often compared to that of a lock and key. The catalytic effect of enzymes depends to a large extent on the way in which they hold reactant molecules in the appropriate relative positions for reaction to occur. In free solution, the chance collisions of the molecules occur in all possible orientations, most of which are inappropriate.
The details of chemical morphogeneses are vague, partly because of their great rapidity, partly because the intermediate forms may be highly unstable, and also because the ultimate changes consist of probabilistic quantum jumps of electrons between the orbitals that constitute the chemical bonds. The virtual form of the molecule-to-be is outlined in the morphogenetic field associated with the atomic or molecular morphogenetic germ. When the other atom or molecule approaches in an appropriate orientation, the form of the product molecule is actualized by means of quantum jumps of electrons into orbitals that previously existed only as virtual forms; at the same time, energy is released, usually as thermal motion. The role of the morphogenetic field in this process is, as it were, energetically passive but morphologically active; it creates virtual structures that are then actualized as lower-level morphic units “slot” or “snap” into them, releasing energy as they do so.
Any given type of atom or molecule can take part in many different types of chemical reaction, and it is therefore the potential germ of many different morphogenetic fields. These fields could be thought of as possibilities “hovering” around it. However, the atom or molecule may not take on its role as the germ of a particular morphogenetic field until an appropriate reagent atom or molecule approaches it, perhaps owing to specific electromagnetic or other effects upon it.
The morphogenesis of crystals differs from that of atoms and molecules in that a particular pattern of atomic or molecular arrangement is repeated indefinitely. It is well known that the addition of “seeds” or “nuclei” of the appropriate type of crystal greatly accelerates the crystallization of supercooled liquids or supersaturated solutions. In the absence of these seeds or nuclei, morphogenetic germs of the crystal come into being only when the atoms or molecules take up their appropriate relative positions by chance, owing to thermal agitation. Once the germ is present, the virtual forms of repetitions of the lattice structure given by the morphogenetic field extend outward from the surfaces of the growing crystal. Appropriate free atoms or molecules that approach these surfaces are captured and “slot” into position; again thermal energy is released as they do so.
The seeding or nucleation of supercooled liquids or supersaturated solutions can also be carried out, although less effectively, with small fragments of unrelated substances; for example, chemists often scratch the sides of test tubes to seed solutions with fragments of glass. These fragments provide surfaces that facilitate the appropriate relative positioning of the atoms or molecules that constitute the true morphogenetic germ of the crystal. In their morphogenetic effect, these seeds resemble the catalysts of chemical reactions.
All the types of chemical morphogenesis considered so far are essentially aggregative. Transformations are less common in nonliving systems. But crystals, for example, sometimes undergo transformation into other crystalline forms, as when carbon crystals in the form of graphite are transformed under high temperature and pressure into the diamond form. Molecules can also undergo transformations, as in the folding of proteins and the reversible changes of shape that occur when certain enzymes bind to the molecules whose reaction they catalyze.