Gerund

"He observes that the latter is, in the case of the Skeptic, to phainomenon, adhering to which in daily life he performs some actions and not others. S. then points out that, adhering to what appears, the Skeptic lives in accordance with the observance of everyday life, which seems to consist in guidance of nature, necessitation of affections, transmission of laws and customs, and teaching of skills."

I think this usage is correct, though vague. But now I wonder if I shouldn't use "by" before the gerund.

Sextus