Capital is a way of counting the product of society. “Three new calves”. The word capitalism come from cap,  and used as in new head of cattle. The great Middle Eastern and Mediterranean empires  were grain and cattle ranches.  This way of counting my cattle on my fingers  was made extendable beyond the five fingers when it became notches on a stick or marks on a surface. The problems with   that way of counting comes when  we treat the marks as  equivalent to the thing counted, and worse when the thing with the marks is treated as ownership of the things counted.