The physical meaning of weak values and measurements can be completely understood with Born rule and the general probability theory. It is known that the weak value of an observable with post-selection F | may be out of the eigenvalue range ofÂ. This is because the weak value of with the post-selection is, in general, not the expectation value ofÂ, but the expectation value ofÂ|F F | boosted by the post-selection.Nearly three decades have passed since Aharonov et al.[1] introduced weak measurements and values. Nevertheless, they remain a subject of debate. Recently, Vaidman [2,3] analyzed the nested Mach-Zehnder interferometer experiment with two-state vector formalism and insisted that the past of a quantum particle could be described according to the weak trace. Li et al. [4,5] challenged Vaidman's claim and insisted that the weak trace could be understood without any unusual probability theory if the disturbances of the weak measurements are considered. However, they agreed with Vaidman with regard to the physical meaning of the weak values.Moreover, Ferrie and Combes [6,7] argued that weak values are classical statistic quantities, which gave rise to a number of rebuttals [8][9][10][11][12]. In particular, Pusey [13] showed that anomalous (imaginary, negative, and unbounded) weak values are non-classical and proofs of contextuality. However, he did not show how the contextuality is responsible for the anomalous weak values.