I think you missed the point of my response. My point is that there are no objective "purposes" for anything. Are you denying that the purpose of a hand saw is to make music? What would be your reason to deny it?
I remember some guy coming to our high school to play Star Trek's opening theme music on his hand saw. I mean, of course, for the original Star Trek, but that was the only Trek at the time. My memory is fuzzy, but the saw probably looked similar to this:
He played it as a caricature of the original music, making it an amusing performance. He did not attempt to sing. He only imitated the "twanging" aspect of the music.
Something I could not help but notice back then is how inconvenient a hand saw is as a musical instrument. The serration and sharp edge of a saw is completely unnecessary to its use as a musical instrument, and makes it dangerous to the musician. The handle was also not shaped to be held in the way that he did, but rather to be used in a back and forth cutting motion. And the bottom of the saw, against the floor, could easily slip if he wasn't careful.
While one can certainly use a hand saw as a musical instrument, it is not well-formed for that purpose.
BTW, no one, not even Aristotle, would deny that one can use a tool for a purpose that it is not well-formed. Nor would Aristotle deny that an entity could, in principle, be well-formed for a number of different sorts of work, and therefore have more than one ergon. That goes for living beings as well.
I want you to adopt a perspective more like Aristotle's for the moment. Did you see the movie AI? Do you remember the Speilberg aliens at the end of the movie?
Those aliens were archaeologists. Humanity had long since gone extinct (and the child in the photo was actually an android), and the aliens were attempting to learn about us as a species. If such an alien were to discover a saw, how do you think it would classify it? What do you think it would recognize about its defining function? Would it be more likely to classify it as a cutting tool, or as a musical instrument?
If you ask me, there is no doubt that these aliens would conclude that the saw is a cutting tool, and if they were to discover that it could also be used as a
crude musical instrument, this would earn it little more than a footnote somewhere.
No one doubts that a hand saw
can be used as a musical instrument, but that is not how I would understand the defining function of a saw based on its construction.
eudaimonia,
Mark