A fortiori

A fortiori is a common Latin phrase in philosophy which literally means "from the stronger." The phrase is commonly used to mean something like "even more so."

Sample usage:

We are sometimes deceived by tricks of light, so we should not always unquestioningly accept what we think we see as truth; a fortiori we can not trust absolutely the testimony of others, since they could also be so deceived, but beyond that they may have some reason to lie.