When we seek the perfect form the head we get judgment, with anger and bitterness toward others. When we seek what is priceless from the heart we have insight, compassion and understanding love for others. They questioned in their hearts. When we question in our heads we come up with a theory. When we question in our hearts we come up with an experience.
Baptism can be a theology to some and to others an experience.
John did not teach a theology of baptism but offered its experience. John gave them an experiential rather than a theological answer. You will known when He baptizes you with the Holy Spirit. There could have been an external audible voice or an inner sense that Jesus was God's beloved Son. Either one would suffice.