Metaphors are dangerous things. On the one hand, it seems pretty much impossible to avoid using them, especially in rather abstract fields like philosophy and science. On the other hand, they are well known to trick one’s mind into taking the metaphor too literally, thereby creating problems that are not actually reflective of the reality of the natural world, but are only perverse constructs of our own warped understanding of it.
Take the metaphor of living organisms as analogous to complex artifacts, which led William Paley to articulate the most famous argument in favor of Intelligent Design -- an argument that, incidentally, has not changed in its broad philosophical outline since the early 18th century. David Hume -- rather presciently, since he wrote before Paley -- pointed out that the metaphor is flawed. Hume argued that living organisms are not like watches, to use Paley’s analogy. They are not machines that are assembled, but organic beings that develop gradually over time. [...]
Hume was right: machines are simply not good metaphors for organisms, and it is time for stubbornly reductionist biologists to move on and search for better metaphors.