Occam’s Razor (OR) is the default to the explanation with the least amount of complexity for any ontological inquiry. OR has 2 warrants.
This is the most obvious justification for employing OR. OR has successfully aided the pursuit of knowledge. Without OR, the body of human knowledge would have been a distorted and bloated unwieldy jumble with a tendency to collapse into technological and pragmatic inefficacy under the weight of many unfiltered conjectures. Through induction we have learned that any complexity within our universe seems to be constructed from a buildup of simple mathematical rules and more basic material entities. To the degree that OR has successfully produced theories that yield efficacious heuristics, processes and technologies that have accomplished our human goals, to this degree we are warranted in our confidence that it will continue to serve us well into the future. But what warrants OR prior to its track record of successes?
Beginning with, what seems unarguably to be, the self-evident fact that thought requires logic, we can come to understand that, with each additional node in any logically interdependent and causally interlaced ontology, there is an increase in possible logical incoherencies and material impossibilities. For each additional node posited in an ontology, there is a greater chance that there will be a logical or material transgression. It may be possible that each additional node added to the ontology can be vetted by assessing its coherence with all other nodes in the matrix of logical and causal relations. However, even if that vetting is not possible, it is still understood from within a basic rationality that there is decreasing probability of total coherency with each additional node. Therefore any mind capable of thought is warranted in defaulting to OR based on the fact that there is a higher probability of logical coherence to the most parsimonious ontology.
So the justification for employing Occam’s Razor is not wholly dependent merely upon the vetting of induction, but also finds justification in the very existence of logical considerations available to any thinking mind, even to an mind devoid of experience and thereby incapable of any inductive assessment.