human beings. Yet they contradicted themselves in this, for all human beings share only certain sights and sounds. They all see the same sun, moon, and stars, and all see such phenomena as clouds and lightning, even though what one group sees may not be the very same thing another sees. Likewise, they share in hearing the sound of thunder. As for the speech and voices they hear from one another, humanity does not share in hearing the very same sounds; rather, each group hears what others have not heard. The same applies to most things seen.

As for smell, taste, and touch, there is no particular object that all people share in perceiving through these senses. What one group smells, tastes, and touches is not the very same thing another group smells, tastes, and touches. The objects may, however, be alike in kind without being individually identical. The same applies to what is known through mass transmission, experience, and intuition: reports may reach one group through mass transmission without reaching others in that way, and one group may experience what others have not experienced. Nevertheless, their knowledge may concern things of the same kind. For example, one group may try certain medicines, while others try medicines of the same kind. They thus share knowledge of the kind, not knowledge of the particular thing tested.

Yet, despite this, they say in logic:

“Propositions based on mass-transmitted reports, experience, and intuition are confined to those who know them; thus no demonstration based on them can establish a proof for anyone else.”

They may be answered: The same applies to things perceived through smell, taste, and touch. Indeed, shared access