Let me add my congratulations here on your paper, which indeed looks likely to bear good fruit.
But I’m still having some trouble getting my head round the concept of “tumours evolving” rather than “populations of organisms evolving new susceptibilities to damage.” It sounds to me to be a metaphorical use of “evolution” that potentially functions to redefine mutations “deleterious to organisms” (the commonest type, because breaking stuff is easy) as “beneficial to tumours”.
It reminds me of Dawkins’ metaphor of the “selfish” gene as the true locus of evolution, which ticked all the population genetics boxes until the primacy of the cell in gene expression began to show it to be an inversion of the real situation.
Our evolutionary theories, after all, are about variation and selection in reproducing populations, leading to differential reproduction, are they not?. It’s not that tumours are not species - but that they are not true reproducing populations. Instead they are aberrations of cell-lines which even themselves are not loci of evolution, unless one has a very atomised view of eukaryote biology. After all, we don’t regard villous cells as “successful” because millions are produced daily, and Betz cells as “unsuccessful” because there are only 50,000 of them. We rightly see their role as subservient to the good of the true functional entity, the organism. How then can one rationally discuss the biological “fitness” of tumours, or even tumour-cells?
Since many BioLogos readers will have no medical background, let me briefly describe tumoursfor them. If a cell line - for example, melanocytes - has a particular genetic propensity, and is subject to the right environmental influences - for example, excessive UV - in just a small proportion of the susceptible individuals one, or a few, of the millions of melacocytes in the body will break free of the usual physiological regulation. If it also bypasses the body’s immune defence mechanisms, it may clone to form a malignant melanoma.
This is deleterious to the parent cell line of melanocytes, because they are destroyed by aberrant cells, deleterious to the organism (the true locus of variation), and ultimately deleterious to the wildly reproducing tumour cells, because they die with the patient… though presumably neutral theory correctly predicts how and why the particular genetic markers involved exist in the human population.
If one may treat tumours as a quasi-species “benefiting” from mutations, and so evolving, then equally one can talk of immune cells “evolving” because genetic patterns of auto-immune disease cause them to proliferate. But is that not ultimately a misleading view down the wrong end of the telescope?
So that’s my first problem. My second is that in rejecting ID arguments regarding evidence for design (not sure which ones - is it the alleged rarity of beneficial mutations, in which case the validity of “tumours” as a true locus of evolution becomes crucial?) you have also apparently rejected any actual divine involvement:
…or regularly require the direct intervention of God to initiate and be sustained. I’m not sure which option is harder to believe.
That seems to be a theological, not a scientific, statement. It always plays well to deny the involvement of God in anything harmful (though of course in the Bible God does actively send tumours, albeit bubonic rather than malignant ones), but the question needs to be argued, not assumed. If it is hard to believe in principle that God (or why not the devil, if one is a believer in fallen creation?) would be associated with these genetic changes, then one is saying that they are excluded from God’s providence.
More specifically, in the context of the belief called “Evolutionary Creation”, in which “evolution is God’s means of creating life”, one is saying that not all evolution is God’s creation, but only some.
In which case, one needs to state clearly what other “demiurge” has its muddy paws in the process of evolutionary creation, and presumably be able to have some emprical way of discerning which parts of creation are designed by God, and which by this other agent (chance, maybe?). That would, it seems to me, only be a particularly subjectively discriminatory form of Intelligent Design.