There is still a lack of consensus over what categorises a phenomena as emergent, particularly in the case of the physical sciences. Arguably one of the most comprehensive works on the topic is Paul Humphreys 2016 book Emergence: A Philosophical Account. I will introduce his taxonomy of emergence, which details features of emergence and provides a classification framework, one of the primary claims being that when emergence is present there is a failure of reduction. My focus will be on ontological emergence, and I will articulate Humphreys concept of fusion emergence and argue there are issues with the basal properties being lost. I continue to dispute the claim that emergence occurs when there is a failure of reductionism, by analysing the definitions and examples provided by Humphreys, and giving an alternative explanation of them. This leads me to present an alternative approach to ontological emergence, comprising of a layered ontology.