I don't think I have much to add to the discussion of the larger issue, but this image resonated for me:
"...in the tail the confluent measureless force of the whole whale seems concentrated to a point. Could annihilation occur to matter, this were the thing to do it.
"Nor does this--its amazing strength, at all tend to cripple the graceful flexion of its motions; where infantileness of ease undulates through a Titanism of power. On the contrary, those motions derive their most appalling beauty from it. Real strength never impairs beauty or harmony, but it often bestows it; and in everything imposingly beautiful, strength has much to do with the magic.
[As] the multitudinous movements of the tail of the whale may express many moods and intentions, the incredible power it embodies is always expressed with gracefulness. So, to me, aikido is rather like the movements of the tail of a whale: full of grace but made of unstoppable, devastating power.
Nicely put and thought provoking.
For example: Is power, in Melville's sense, a sufficient cause of this physical grace (or martial efficacy) even if it is accepted as a necessary one? Metaphorically -- does the whale need to understand more than how to thrash its tail (powerfully) to glide through the ocean with grace and seeming effortlessness?