Student or Learner
If you have a burning desire to know the origins of "caustic," you're already well on the way to figuring it out.
why does this sentence herein use to figuring it out, not to figure it out? thanks.
well on the way to figuring it out.
The phrase is, 'well on the(your) way to...'
so 'to' is a preposition, which must take a noun.
'to figure (something out)' is the verb as the infinitive. BUT - the 'to' in the infinitive form of the verb is not the 'to' in your sentence, the preposition 'to'.
Since the preposition 'to' takes a noun, the gerund/verbal noun of 'figure' as in 'to figure' , is 'figuring'.