As a science, psychology gains knowledge through observation and measurement. this approach is called "empiricism", and the step-by-step implementation is called the "scientific" method, which follows systematic steps in a bias-free way, in order to obtain "reproducible" results.
Empiricism is an essential part of the scientific method since speculations and theories must be watched and tried to be viewed as precise. Empiricists will in general be skeptical that anything can be known for certain and, in this way, they tend not to put stock in creeds or total certainties. Empiricism is a philosophical conviction that expresses your insight into the world depends on your encounters, especially your tactile encounters.