No, Ptolemy did.
He made many experiments and observations in the field of physics in general.
Having two independent observers increases the reliability and validity of the observations by reducing bias and increasing the consistency of the results. It also helps to ensure that the findings are not due to chance or individual interpretation.
replication
Scientific Theory is tested by observations and experiments predicted by the theory. If the observations confirm the theory the theory is validated if not the theory is not validated. Experiments themselves need validation, often there are errors in the experiments or observations, e.g Michaelson and Morley Aether experiment and red shift observations.
If it is possible, at least two people should confirm the accuracy of facts and the validity of assumptions during the problem solving process. This helps ensure accuracy.
Newton confirmed his hypothesis about gravity by developing the Universal Law of Gravitation, which described the force of gravity between two objects. He used this law to predict the motion of the planets and the Moon, which matched observations made by astronomers, confirming the validity of his theory.
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This comes from the scientific method. A hypothesis is a rational explanation for an observed phenomena. When multiple researchers confirm the observations in agreement with the hypothesis, the explanation of the set of observations can be referred to as a theory.
In the language of assessment, a test that measures what an assessor intended it to measure is referred to as having high validity. Validity ensures that the test accurately reflects the specific skills, knowledge, or constructs it aims to evaluate. This can encompass various types, such as content validity, construct validity, and criterion-related validity, each serving to confirm the test's relevance and effectiveness in assessing the intended outcomes.