No, the human ear cannot distinguish two pure tones that have the same frequency and amplitude. When two pure tones have the same frequency, they are perceptually fused together and perceived as a single tone with the same frequency. This phenomenon is known as a "just noticeable difference" (JND) or a "difference limen."
The human ear can distinguish differences in frequency when two tones have slightly different frequencies. This ability is known as frequency discrimination. The threshold for frequency discrimination varies depending on the frequency itself. For example, the human ear is generally more sensitive to differences in low frequencies compared to high frequencies.
However, when the two pure tones have exactly the same frequency and amplitude, the ear cannot perceive any difference between them, and they will be heard as a single tone. It is important to note that this applies to pure tones specifically and not to complex sounds or tones with different harmonics or spectral content.