The definition of "scientific theory" has not changed to specifically support the claim that the theory of evolution is a scientific theory. The term "scientific theory" has always had a specific meaning within the scientific community, and it refers to a well-substantiated explanation of some aspect of the natural world that is based on a body of evidence and has undergone rigorous testing and scrutiny.
The theory of evolution, proposed by Charles Darwin and supported by overwhelming scientific evidence, meets these criteria and is widely considered a scientific theory. The understanding and acceptance of the theory of evolution have evolved over time as new evidence has emerged and scientific knowledge has advanced. The scientific community continually examines and tests evolutionary theory, refining and expanding our understanding of the mechanisms and processes involved.
It is important to note that the term "theory" in a scientific context does not imply uncertainty or guesswork as it might in everyday language. In science, a theory is a well-substantiated and highly supported explanation that has withstood extensive testing and scrutiny. It is the highest level of confidence we can have in an explanation based on the available evidence.
While there may be debates or discussions about specific aspects of the theory of evolution within scientific circles, the overwhelming consensus within the scientific community is that evolution is a well-established scientific theory supported by a vast array of evidence from various disciplines, including paleontology, genetics, comparative anatomy, and more.
The recognition of the theory of evolution as a scientific theory is not a result of a change in the definition of "scientific theory" but rather stems from the accumulation of evidence and the scientific community's adherence to rigorous standards of inquiry and evidence-based reasoning.