While it’s true that scientists and inventors built on the work of their predecessors, some were especially important. If the invention of the telescope is particularly important let me commend to your attention Galileo himself who developed the best telescope of his day, among many other great accomplishments.
The suggestion that Copernicus’ discovery followed from the invention of the telescope will need quite a cite, I’m afraid. Copernicus did not use a telescope – it hadn’t yet been invented in his time.
A key question is: How long would a discovery have been delayed if its discoverer hadn’t lived? In the case of Mendel, we know the answer: 35 years. A rather long delay, I think, given the simplicity and importance of Mendel’s discovery to the understanding of genetics and evolution. For this reason, Mendel could be called a great discoverer.
Unfortunately, the fact that we know the delay would have been 35 years argues against Mendel’s influence. The only reason we know exactly how long the delay would have been is that … there was such a delay. Though published in a scientific journal, Mendel’s discovery was completely ignored for 35 years. :smack:
Mendel’s Laws were an “idea whose time had come” … 35 years after Mendel’s discovery … when four separate researchers independently discovered the Laws and/or stumbled on Mendel’s paper.