The field of science is continously changing. The filtering of information is extremely important when defining the boundary of knowledge. Yet, equally important, is our inquisitive nature and unbound curiousity that is driven to speculate on the nature of life. This set of knowledge that exists beyond the known boundary that defines science should not be discarded so abruptly.
We certainly cannot prove all aspects of reality because our perception is a subset of the univserse. Better yet, our knowledge is a small subset bounded by the confines of science, which is a miniscule speck in relation to absolute truth. Therefore, we truly know nothing.
Imagine yourself born into a world where the artificial world does not yet exist. Life - as we know it today - consists of the natural world and the artificial world. Humans create the artificial world to understand the natural world (reality) and entertain our time.
If the artificial world was pre-set to zero, the boundary of science that we define would revert to a point. Therefore, speculation would initially rule the process. When the boundary of objectivity closes in, ideas stir in the background (outside the boundary) without as much filtering. Once the basis of truth grows, we can more readily verify or constrain our ideas.
The rate in which the outer boundary of science grows is proportional to our drive to seek the unknown. The area existing beyond the boundary is all speculative by definition. Placing all emphasis or faith in science is itself a closed system of thought.
The level of certainty due to science is only as strong as our current development. If society tends toward increasing complexity and we exist at a finite point in time, then we are relatively simplistic. Future generations will likely believe so as the boundary of science continually expands. But to do so, the outer boundary must be broken.
There is a reason why the chaos that encompasses life is hidden from us. Our mind cannot withstand the bombardment of stimuli because there exists a limit such that information cannot be compartmentalized.
We progressively seek to understand higher levels of chaos, but the process must be slow to limit stress. Due to these constraints, the possibilities that exist outside our mind is immeassurable. Therefore, any speculative claim that is outside our scope could certainly be valid.