Abstract
It is shown that, at the time of Euler and Lagrange, a belief led to an assumption. The assumption is applied to derive the principle of least action from the vis viva. The assumption is also applied to derive Hamilton's principles from the vis viva. It is shown that Hamilton, in his 1834 paper, countered the assumption of the earlier mathematicians. Finally, Hamilton's law, completely independent of the principle of least action and Hamilton's principles, is obtained to verify the foregoing assertions. The unifying laws of classical mechanics, contained within Hamilton's 1834 paper, are identified