cogent, telling, weighty
Meaning: powerfully persuasive; "a cogent argument"; "a telling presentation"; "a weighty argument"
This the one cogent reason why he must not, could not, die....
But a good deal had been said which, though not perhaps capable of convincing the unprejudiced American or Frenchman, had been regarded as cogent arguments to country-bred Englishmen.
If, therefore, corporeal matter holds the forms which it receives, not only while it actually does something through them, but also after ceasing to act through them, much more cogent reason is there for the intellect to receive the species unchangeably and lastingly, whether it receive them from things sensible, or derive them from some superior intellect.