The phrase "to blur the edges" means to make things less clear or distinct. It can refer to softening the boundaries between different ideas, concepts, or objects, making them less defined or easily separated. Full definition
Our bodies and minds hold a type of intelligence that we're not taught about in school, and being introduced to it in our adult lives blurs the edges of our reality. (vikasayoga.com)
It has deliberately blurred the edges between planning, avoidance and evasion such that I have heard one member of HMRC's anti-avoidance unit proclaim that investing in an ISA is at the less egregious end of the avoidance scale; as if it can in any way be described as avoidance. (lawyer-monthly.com)
Next came circles with blurred edges, like blazing catherine wheels, diamond shapes, diamonds within circles, chevrons and stripes. (theguardian.com)