I believe we should learn through experience. If something worked in the past thats how we should move forward in the future. What harm would it do to read books written by other people and apply the knowledge from those books to our own experiences in life. I believe a good understanding of high school mathematics is also important. (algebra, Calculus I, geometry, boolean algebra, discrete mathematics and certainly statistics, there may be some more).

Is there any way to get rid of this constant uncertainty? — AnonThinker25

No but oddly, we make plans as if this uncertainty doesn't matter. Sometimes our plans go awry exactly because of this uncertainty but many times our plans do work out as if this uncertainty didn't exist. I guess it's a matter of determining the causal import of things that affect us. Some things are causally important and we should factor them into our plans while others are causally insignificant and can be ignored. To know the difference between these two is called intelligence or wisdom.

Be uncertain. Nothing wrong with it.

Try not to jump off buildings because you are uncertain that gravity always works, though.

Richard Feynman used to talk about certainty often...about what we actually know. He was a guy who "knew" lots, but his take might disturb you, because he was of the mind that we "knew" very, very little with certainty.

I'm a bit solipsistic myself.

No big deal for me.

The easiest response is to assert fallibilism, that we can know things without the certainty of their truth.

Certainty in itself isn't the end all and be all of understanding and getting along well with others. Older forms of philosophical and empirical theorization pride themselves on being 'certain' of the grounding in truth in such things as logic or God, but their certainty is the reification of arbitrary meanings which amounts to certainty in the unexplanable. Newer modes of inquiry abandon the search for certainty, replacing it with what I think is the more important and clarifying value, relationality. Philosophies and empiricisms which idolize certainty leave us with explanations of our connections with other humans in terms of causal mechanisms which do not admit of further, deeper elucidation beyond arbritrary assocaition.

The thing to get rid of is a desire for certainty. It's important to learn to be comfortable with things not being certain.

In logical terms, if you seek certainty, then religion is for you. Alternatively, you could limit your mind to those areas of science which deal in certainty, such as Euclidean geometry and Newtonian physics.

If you have the courage, you may choose to embrace uncertainty. In the history of the Universe, the development of Homo Sapiens is a vanishingly insignificant event. Isn't that an invigorating thought?

There are many situations which apparently require me to make assumptions instead of actually knowing what is true and what is not. Is there any way to get rid of this constant uncertainty? I feel like I become really uncertain about many things if I don't constantly check them or if I'm unable to do so. — AnonThinker25

I'm not sure I'm clear on what you mean by "knowing?" Part of the problem may just be that you think knowing X means that you have complete certainty or absolute certainty. Much of what we claim to know is probabilistic, that is, we know with a degree of certainty. I know the sun will rise tomorrow with a very high degree of certainty (here I'm talking about objective certainty - based on good reasons or good evidence). I know my car will start with a high degree of certainty. I don't know with absolute certainty, but that doesn't mean there is good reason to doubt that my brand new car will not start. What you need to ask yourself is, "Are there good reasons to doubt?" Just because you could be wrong, that doesn't mean you should be skeptical. In many cases there are good reasons to doubt the doubt, we shouldn't doubt willy-nilly.

I feel like I become really uncertain about many things if I don't constantly check them or if I'm unable to do so. — AnonThinker25

Could be OCD, or some degree of it.

I started having trouble being certain about anything I can't perceive through my senses. — AnonThinker25

Don't worry. Read some Berkeley then you won't even believe your senses. Your senses are the only evidence you have that there's anything out there in "external reality." But that's no evidence at all! What if your senses are all that there is? And that there is nothing at all "out there?"

Nothing would be changed. Your senses would still be exactly the same as before.The existence of an external reality is a superfluous assumption. It's not needed to produce your senses.

Berkeley, being a bishop in the Catholic church, thought the cause of our senses was God. From a modern perspective, this is essentially the point of view of simulation theory. It's the great computer in the sky that creates our the illusions of our senses. Nothing is real. We only have our experience of the simulation.

This theory denies the existence of material substance and instead contends that familiar objects like tables and chairs are only ideas in the minds of perceivers and, as a result, cannot exist without being perceived.

Is that not exactly what simulation theory says?

https://en.wikipedia.org/wiki/George_Berkeley

By the way it's not entirely clear from your post whether this is an intellectual concern or whether it's bothering you personally in some way. If the latter, probably best to get "out" more. LOL. Jump into the simulation, the water's fine!

Sounds a little like you’re conflating mathematic probability with logical certainty?

Empirically there is necessary doubt (due to inaccuracy of measurements) and logically there is no doubt (although confusion and missteps happen due to human error - that is a matter of care not mathematical inaccuracy); meaning if I say 2+4+6= 11 I’ve made an ERROR, the solution not being wrong due to the inaccuracy of the abstract numbers (because they cannot be inaccurate).