Thomas Aquinas,
Summa Theologiae — Question 63 - THE MALICE OF THE ANGELS WITH REGARD TO SIN…
“ Consequently, no creature of a lower order can ever covet the grade of a higher nature; just as an ass does not desire to be a horse: for were it to be so upraised, it would cease to be itself. But herein the imagination plays us false; for one is liable to think that, because a man seeks to occupy a higher grade as to accidentals, which can increase without the destruction of the subject, he can also seek a higher grade of nature, to which he could not attain without ceasing to exist. ”
