No, currently humans cannot defy gravity and fly without the assistance of machines or external devices. The human body is not naturally equipped for sustained flight. While humans have developed various methods and technologies to enable flight, such as airplanes, helicopters, and jetpacks, we do not possess the physical adaptations required for unassisted flight.
The ability to fly typically requires mechanisms such as wings, propulsion systems, and aerodynamic structures, which are not inherent in the human anatomy. While humans can experience temporary and limited forms of flight through activities like skydiving, hang gliding, or using wingsuits, these activities still rely on the aid of specialized equipment to counteract the force of gravity and generate lift.
In summary, humans do not possess the inherent capability to fly without the aid of machines or external assistance. Flight remains primarily within the realm of technology and devices specifically designed for that purpose.