I think all verbal truths are relative, changing and expanding with time (ex: Galileo, Newton, Einstien, Bohr).
The Ultimate Truth if there even is one,,cannot be put into words or experienced with the thought mind, for these would be only approximations limited by concepts, words, judgements, and imagination. We can not focus on it, for the very act of focusing causes distortions to our preception (ex: when we focus on something because of fear we see only what fear causes us to focus on).
IMO 'Ultimate Truth" is the "Ultimate Mystery" never to be understood. IMO ther is no way to percieve it, we may have many experiences with alter states of consciousness be it drug induced or thru quieting the mind that "feel" like this is it this is the ultimate truth, my opinion is, it may be only a better sense or more expanded view but not the end as the concept of Ultimate Truth implies. I think scientist and those who practice other forms of inquiery will never find it because there maybe an infinite amount of layers of covering it over.