Consider your lyre: you can't tell just by looking at it how the strings are pitched. At most, you know that you're in a mode based on eight degrees. It's the same with the te`amim; they only indicate that a hierarchical, diatonic-chromatic mode is used. But you may infer which mode is used by how the melodic line relates to the verbal line, in particular to the verbal grammar. SHV goes into this in her book and, I think, her score MESSAGE BIBLIQUE INTEGRAL.