"We are to admit no more causes of natural things than such as are both true and sufficient to explain their appearances. Therefore, to the same natural effects we must, as far as possible, assign the same causes." (Newton)

When you are faced with something that can not be explained by the principles you understand, does that mean that the phenomenon ceases to exist ?

So, by that line of thinking - the diffraction of light could not be explained until we had a new theory about light being an electromagnetic wave, so should we have ignored the experimental results altogether, because it's more convenient to what we can understand?