Lamarck & Darwin Compared

 

The important distinction that must be made between Jean-Baptiste Lamarck's position and Charles Darwin's is that the former believed that animals acquired characteristics. In other words, organisms or animals can change while alive. Darwin, on the other hand, stressed the inheritance of characteristics, not their acquisition during the existence of animals.

Nonetheless, surely an animal has to acquire a characteristic before it can be passed onto - or be inherited by - future generations. Yes, that's true – though only over time. That is, individuals don't acquire characteristics over life-times. Though over time species may acquire characteristics. Those characteristics, though, will be too small to be noticed by one generation and will certainly not be noticeable over the lifetime of an individual animal.

Is this true of all species? What about the microscopic ones which have very short lifespans? Is is literally impossible for one such species to acquire a characteristic during its own lifetime?

The Lamarkian position is that “the constant craning of a giraffe to reach leaves high in a tree would alter its sperm or egg that its offspring would be born with longer necks” (114). This seems like a ridiculous idea – though only in retrospect! That is, only in the retrospect provided by knowledge of Darwin's theories. Nonetheless, the argument is still that repeated behaviours or habits of animals has a literal affect on sperms or eggs. Thus if the sperm or eggs are affected by this behaviour, then they will automatically produce offspring that will be different in some small or even large way.

Darwin's position, on the other hand, is that there is no direct relation between animal behaviour and changes in that animal's sperm or eggs. What actually is argued about behaviour X (say reaching the higher leaves) is that it's more likely to survive and thus pass on its genes because of behaviour X. The eggs or sperm aren't changed due to behaviour. Though the behaviour leads to a situation in which that animal, and animals like it, are more likely to survive. Thus giraffes with longer necks are more likely to survive. And, because of that, those giraffes which have longer necks are more likely to pass on the long-necked gene than those giraffes with shorter necks. Thus, over time, short-necked giraffes die out because less of them survive. And the less of them that survive (due to having short necks) means that they can't pass on their genes. Short-necked genes aren't passed on; though long-necked genes are.

Thus behaviour doesn't affect genes. What does affect genes, in fact, is entirely random. Though if a random change in the structure of genes produces giraffes with long necks, and long necks are more likely to secure survival, then the genes for long necks are more likely to be passed on simply because giraffes with longer necks are more likely to survive than giraffes with shorter necks.

Kurt Gödel's Theorems & Physics

It's often asked whether or not Kurt Gödel's theorems can be applied outside mathematics. John Horgan certainly applies them to the theories of physics. Or, more accurately, he writes that

 

“Kurt Gödel's incompleteness theorem denies us the possibility of constructing a complete, consistent mathematical description of reality” (6).

Clearly there's a jump here from Gödel's mathematical incompleteness theorems to physical reality. Or, more accurately, from Gödel's theorems to a “consistent mathematical description of reality”. Is that jump justified?

Well, for a start, physics is utterly dependent on mathematics. Thus if all descriptions of reality in physics involve mathematics, and mathematics is subject to Gödel's theorems, then that must pass over to the descriptions of reality which are offered by physicists. In other words, if a mathematical system must be incomplete (or not entirely provable), then that description of reality must be incomplete (or not entirely provable). The two must fall and rise together.

More meat is put on this idea of whether or not Gödel's theorems are applicable to theories about reality when John Horgan says that the “British physicist John Barrow argued that Gödel's incompleteness theorem undermines the very notion of a complete theory of nature” (69). We move again from mathematical systems to the incompleteness of a “complete theory of nature”. It can be said here that Barrow is simply transferring the incompleteness of mathematics to the incompleteness of a “complete theory of nature”. Again, does the former necessarily pass over to the latter?

In more detail: Godel established that "any moderately complex system of axioms inevitably raises questions that cannot be answered by the axioms". Then Horgan moves onto to say that the “implication is that any theory will always have loose ends”.

Many scientists accept this application of Godel's theorems to physics, including Moravec, Roger Penrose and Freeman Dyson. The latter says:

“Since we know the laws of physics are mathematical, and we know that mathematics is an inconsistent system, it's sort of plausible that physics will also be inconsistent.” (254)

Thus what we have here is a logical argument:

i) Physics is mathematical.

ii) Mathematics is an inconsistent system.

iii) Therefore physics must be an inconsistent system (or simply incomplete).

The only problem here is seeing the entirety of mathematics as a single system (which itself incorporates systems). Perhaps it is.