Every bit of scientific information is "THEORY". We have the theory of relativity , which we use to create nuclear reactions and send rockets into space. Why is this still called a theory? Because science allows for paradigm shifts. That doesn't mean the shift shows the former to be incorrect, rather the shift is when additional information is added, thus we first had Newton's law, Einstein built on that for relativity, and scientists (physicists) today abound with new speculations such as, it may be possible that the universe at one time had speeds faster than the speed of light. So each theory allows for the shift, not negating but building on the previous analyses. Another example is the PTE, which contains many "empty" or unnamed spaces. We know by atomic weights of elements that these exist, but science has not found them yet. Eventually inorganic chemistry will fill in the PTE. Also think of the genome project. In 1953 the "discovery" of DNA didn't mean that there was no DNA before, only that scientists hadn't seen it. It takes time and instruments to understand the natural world. So the theory of life begins with knowledge of punctuated multi-generational changes within a species, continues to DNA and eventually the paradigm shift to what makes things alive. It's not a stretch anymore, we understand how and why theories must allow for change. This is science.