"Science is initially based on assumptions..."

No, not at all. It's based on observations. Hypotheses attempt to explain what is observed, and if they are not soon falsified, they rise to the level of theory. Recently I proposed that dark matter was simply the gravitational effect from matter at other times. It took me a couple weeks to consider my hypothesis in conversation with a particle physicist before I realized I could falsify my hypothesis, because dark matter is not concentrated where visible matter is, which would be the case were my hypothesis correct.

It is no slight to have a theory falsified. I did it to myself. It is simply how false hypotheses are winnowed down leaving only those that have not yet been proven false, which enables the window of possibility to be continually narrowed, availing us the ability to close in on what is actual. We never actually arrive, but we keep getting closer.

Organisms with magnetite in their neurons, like us and certain bacteria, do generate magnetic fields. Not all bacteria do. Therefore consciousness, not being limited to living things that generate magnetic fields, cannot be the product of magnetic fields. The hypothesis is falsified by creatures exhibiting consciousness that do not also exhibit magnetic fields. It's not a slight on the hypothesizor that the hypothesis is falsified. It is good science, and has enabled the things that could possibly be the source of consciousness to be narrowed down.

That is how science works. Nothing can be proved. Things can only be disproved, which leaves an ever smaller potential list of things that have not been disproved. That's literally all the scientific method is.