If two planets were truly identical in every aspect, then there would be no inherent differences between them. By "identical," we assume that they possess the same size, mass, composition, atmospheric conditions, geological features, and any other relevant characteristics.
However, even in such a scenario, it's important to consider that the planets would exist within a larger universe, and their locations within that universe could lead to differences in their environments. Factors such as their distances from their host stars, the presence of other celestial bodies in their respective systems, and the overall cosmic environment would still influence their individual experiences.
Additionally, even if the planets themselves were identical, there could still be variations in the life forms and ecosystems that evolve on each planet. The presence of different species and the effects of evolutionary processes would introduce diversity and uniqueness, even if the planets started with the same conditions.
In summary, while the planets themselves might be indistinguishable in every way, the broader context in which they exist, along with potential variations in life and ecosystems, could still lead to differences between them.