A fair question. I am time limited here now but I’ll explain briefly.
Firstly there are pitfalls when asked this question (especially by one who appears a little hostile to the idea). ok…
1. We need examine the nature of knowledge and what constitutes it.
2. I may just as equally ask YOU the same question why you believe in a globe earth. 4 Your question comes from an orthodox standpoint which holds assumptions.
3. Your stance assumes you hold truth and I must “prove” what I have come to believe.
4. You believe you do not have beliefs.
5 This fact establishes an unfair playing field.
6. I started as a sceptic to flat earth (as do most serious converts).
7. I tried to debunk it.
8. You assume that ‘math’ and ‘physics’ can prove reality.
9. you covet certain truths as axiomatic.
10. You hold an orthodox science bias which you cannot extract from in order that new information which conflicts with your paradigm is not considered and tends to be mocked and ridiculed
11. this is a psychological fact known as cognitive dissonance.
12. Actual science is proving that NO curvature OR motion of the earth in space is evident.
13. by actual science – I refer to science based truthfully on an unbiased or skewed application of the scientific method – empirical repeatable observation and measurement.
14. Funded academic science has become untrustworthy due to inherent corruption from funding sources, group think (peer review and career sustaining – nobody will go against orthodox paradigms), science has become path dependant upon previous theory.
15. ‘flat Earth’ has become a timely test of the true ability of human consciousness to break out of moulds which have restricted thinking and stagnated human advancement due to exploitative human systems (eg finance and social control).
16. Science is NOT the incorruptible and pure path to Truth that its proponents pretend – human judgement and fallibility does indeed factor significantly.
17. I come from a varied educated (some science) background. I am and always have been an “open-source thinker” (this helps adopting new concepts rather than clinging to old ones).
18. IF we continue to demand “proof” that fits our biases we begin a path of self-deception and this has factored into human scientific thinking
19. I spent 12 months researching the SERIOUS data coming to light
20. I cannot here sum that for your perusal.
21. I have done some of my OWN experiments and observations based on current math and understanding and found it does NOT hold truth empirically – eg NO curve is observable across a large body of water near where I live – almost 50 km and a city skyline can be measurably observed to NOT fall below the predicted earth curve (math based). We can see too far across the Earth – now high-powered optics available to a wide range of people who are discovering this fact – again empirical observation conflicts with academic orthodox assumptions we are taught and told (beliefs).
Many other anomalies are coming to light and you need to investigate seriously and with an open mind free of the above biases. Hope this gives insight.