Board Thread:General Discussion/@comment-26907577-20191031134344

Here is the conundrum: The quantities don't add up. 
 * Undyne melts when dying.
 * The Amalgamates melted a long time ago.
 * If Determination allows human SOULs to persist after death, and Boss Monster SOULs persist after death, then (barring another explanation) Boss Monster SOULs probably have Determination.
 * If Determination causes monsters to melt, and Undyne melts, then (barring another explanation) Undyne probably has Determination.
 * So,
 * Boss Monster SOULs have enough Determination to persist, but not enough to melt.
 * Undyne has enough Determination to melt, but not enough for her SOUL to persist.