In his Origin of Species Darwin quoted six times the Latin sentence “natura non facit saltus” (“nature makes no leap”, it is a maxim expressing the idea that natural things and their properties change gradually, in a continuum, rather than suddenly). All the times Darwin used such quote to justify his idea that species arose gradually, by means of small advantageous increments, contra what he called “the theory of Creation” supposed discrete:
As natural selection acts solely by accumulating slight, successive, favorable variations, it can produce no great or sudden modification; it can act only by very short and slow steps. Hence the canon of “Natura non facit saltum,” which every fresh addition to our knowledge tends to make more strictly correct, is on this theory simply intelligible. (chap. XIV)
In a sense, all Darwin’s philosophy of biology is based on such dictum (he even calls it “canon”). Unfortunately, Darwin’s gradualism based on a supposed universal continuity in nature is flawed.
First, continuity is not at all a universal physical law, nor is a fundamental cosmological principle. In the cosmos there is continuity in some phenomena and there is discontinuity in others. There is continuum from certain perspectives and there is discontinuum from others. Perhaps there is only a point of view according to which natura non facit saltus is really true everywhere: in the cosmos nowhere absolute void can exist, nowhere there are true “holes” of nothingness, so to speak. Anyway this particular meaning has nothing to do with biology and what Darwin had in mind. Darwin has no excuse. He couldn’t know quantum mechanics, however he surely knew simple examples of discontinuity: when a continue increasing force is applied to a rope, there is an instant when the rope fractures, and this is a discontinuity; a water drop forms gradually on the orifice of a bibcock, but it falls suddenly only when its weigh reaches a certain threshold value.
Second, origin of species is exactly a field where continuity doesn’t hold. In fact origin of species involves the construction of complex systems and functionalities, and the arise of functionalities appear always in saltus during the process of construction. In general, when we deal with functionality “natura non facit saltus” is untrue. Biology is eminently a field of big functional saltus, exactly as human engineering and technology.
Darwin’s idea that biological functions/organs/apparatuses can arise by small changes each giving an advantage (gradualism) is false and contrary to any evidence. In all fields of engineering an assembly converging to a main function is usually composed of non functional steps. Example: an airplane is assembled in many small steps but the fly function arises only at the end, when the last step is ok. Analogously in organisms all functions work after an assembly of steps giving no advantage. Example, the visual system works only when at least three complex sub-systems work together according to common hardware-software specifications and protocols: a photoreceptor, a brain region decoding the signals and an optical nerve as interface transmitting signals between the two. The assembly of these three sub-systems involves countless phases that individually provide no advantage.
Darwinists cannot point to embryology to help their case. Embryology is another field full of functional discontinuities, which have nothing to do with Darwin’s gradualism. First, embryological development isn’t a Darwinian evolution because is a fully directional process and a teleological result of a long series of morphogenetic signals and pre-programming. Second, all embryological developments indeed show that Darwinian gradualism is nonsense because in such developments, before becoming functional, organs and apparatuses pass through countless non functional, non advantageous steps (exactly as in any assembly of engineering systems). If you put embryos and fetuses in the wild you see that they immediately die indeed because their main systems are rudimental and still don’t work.
Nor Darwinists can point to the growth of the organism from birth to adult state for justifying their functional gradualism, because at birth all systems are already in place, and no new system arises after during the growth until the adult state.
The Darwinian dumb axiom that all bio-systems are functional and give advantages just from the beginning of their developments is pure engineering blasphemy. Organisms are not built from natural selection acting on many small advantageous mutations, exactly because in any construction complex functions arise by saltus. Darwinists should try to prove e.g. that an organism’s apparatus can arise gradually. They could learn the principle of “irreducible complexity”: an IC function has no functional precursors. In the example above of the visual system, it is IC with regard to its three sub-systems. Of course these three sub-systems are just very complex and involve in turn many nested IC sub-sub-systems. IC is a hierarchical concept and can be applied at many levels.
Moreover we have also to consider the correlation of apparatuses, i.e. the integration of all apparatuses in a organized whole. When I hear an evolutionist even say that the human body (the most complex system in the universe) arose by Darwinian RV+NS gradualism I wonder if he ever read a manual on human anatomy, technically describing the giant hierarchy of interrelated parts and functions of the human body (my own manual is 6 books, ~6,000 pages overall). Not only organisms contain countless nested IC systems, these IC systems are integrated in a perfect hierarchical organization, which no Darwinian gradualism can produce.
Darwin was a specialist in non sequitur. One of them is the unsupported huge extrapolation of macroevolution from minimal trivial variations (microevolution). Another was indeed his dreamed “philosophy” of a universal biological continuity erroneously inferred from a Latin sentence that is not a rule without exceptions.