Most of Western music since the Renaissance has been based on a seven-note scale known as the diatonic scale, but when did the scale originate  <b> A fragment of a bone flute excavated at a Neanderthal campsite has four holes, which are spaced in exactly the right way for playing the third through sixth notes of a diatonic scale  </b> The entire flute must surely have had more holes, and the flute was made from a bone that was long enough for these additional holes to have allowed a complete diatonic scale to be played
<b> Ttherefore, the Neanderthals who made the flute probably used a diatonic musical scale
The first introduces the phenomenon that the argument as a whole seeks to explain; the second gives a reason to rule out one possible explanation.