Scientists get too hung up on finding the mechanism, implying that there is only one. And even when sense triumphs, and they acknowledge a second mechanism, they get too hung up on which is the main mechanism, as if what is the major mechanism cannot vary person to person or time to time within a person.
For example, oncologists who pontificate that cancer is a genetic disease – and nothing else- ignore data that contradict their view, and vice versa. When the oncologists who believe cancer is a genetic disease bother to acknowledge a second mechanism (mitochondrial dysfunction), they say it is of secondary importance, that is, that mitochondrial dysfunction is always a consequence of nuclear mutations. Really? Could mitochondrial dysfunction not sometimes precede and abet nuclear mutations?
Because of the intrinsic complexity of the selection process – and a successful tumor, e.g., is a product of multiple successful selections – it is a rule that multiple pathways exist to the same outcome, and thus one should not obsess on THE mechanism or on the MAJOR mechanism, because I can all but guarantee the successful tumor will have some cells with mostly dysfunctional mitochondria and some cells with mostly functional mitochondria, some cells with few nuclear mutations of consequence, and some cells with many nuclear mutations, some with consequences, and some secondary to mitochondrial dysfunction, and the oncologist must figure out a complex strategy of dealing with these chimeras. Anything less will yield less satisfactory outcomes.
The same goes for other phenomena of living beings – multiple pathways to the same endpoint, rarely a single mechanism and no invariant MAJOR mechanism.