Does Kant focus this way on the individual's experience and reason? It seems to me that we only reach some provisional truth when communicating minds agree on

Does Kant focus this way on the individual's experience and reason? It seems to me that we only reach some provisional truth when communicating minds agree on their experiences and how they are reduced by reason to concepts. Only by formal processes for reaching agreement with past and candidate truths by multiple individuals do we avoid error, delusion and fantasy.