Here's why:

* Multiple observations: The fact that several scientists independently make the same observation strengthens the validity of the finding. It's less likely to be due to chance or error if multiple researchers reach the same conclusion.

* Independent research: When scientists work independently and arrive at similar conclusions, it adds to the weight of the evidence.

* Scientific consensus: Over time, as multiple studies and observations support the same idea, a scientific consensus emerges. This means the scientific community widely accepts the finding as a likely explanation for the observed phenomenon.

It's important to note that scientific consensus can evolve over time as new evidence emerges. However, it represents the current best understanding of a scientific phenomenon based on the available evidence.