In the same way the chief priests, along with the scribes, were also mocking him among themselves and saying, ‘He saved others; he cannot save himself. Let the Messiah, the King of Israel, come down from the cross now, so that we may see and believe.’ Those who were crucified with him also taunted him. (Mark 15: 31-32)

The chief priests were mostly sober and rational men. Their taunt, "so we may see and believe" was meant to be ironic. But it also reflected their worldview, they believed what could be observed.

The Temple priests were mostly Sadducees. As such the priests tended to be scriptural literalists, highly skeptical of interpretation. They rejected the immortality of the soul and the possibility of life after death. They considered the Pharisee's belief in the messiah a dangerous fantasy.

The chief priests were deeply committed to their inherited faith. But for them the faith was a rational system of ritual discipline and ethical behavior that rejected any mystical realm beyond their rational apprehension.