What can I know with complete certainty?

[Compassionist]

I am completely certain of the following:

1. I am conscious.
2. I am typing in English.
3. I am not all-knowing.
4. I am not all-powerful.
5. I change.
6. I can't do lots of things I really want to do e.g. go back in time and prevent all suffering, inequality, injustice, and deaths and make all living things forever happy.
7. I do some things even though I don't want to do them. Here are some things I have done, currently do or will do even though I don't want to do them:

1. Breathe
2. Eat
3. Drink
4. Sleep
5. Dream
7. Pee
8. Poo
9. Fart
10. Burp
11. Sneeze
12. Cough
13. Age
14. Get ill
15. Get injured
16. Sweat
17. Cry
18. Suffer
19. Snore
20. Think
21. Feel
22. Choose
23. Be conceived
24. Be born
25. Remember some events that I don't want to remember
26. Forget information that I want to remember
27. Die

I am almost certain of the following:

1. I and all the other organisms currently alive will die. Every second brings all organisms closer to death.
2. My body, other organisms, the Earth and the Universe really exist and they are not part of a simulation or hallucination or dream or illusion.
3. Other organisms e.g. humans, cows, dogs, cats, chickens, pigs, lions, elephants, butterflies, whales, dolphins, etc. are sentient beings who feel pain.
4. Being a non-consumer is more ethical than being an autotroph, being an autotroph is more ethical than being a vegan/herbivore, being a vegan is more ethical than being a vegetarian, and being a vegetarian is more ethical than being an omnivore or carnivore.
5. Gods do not exist.
6. Souls do not exist.
7. Reincarnation does not happen.
8. Resurrection does not happen.
10. Organisms evolved and were not created by God or Gods.
11. 99.9% of all the species to evolve so far on Earth became extinct in 5 mass extinctions long before humans evolved.
12. Humans and other organisms do not have free will. Our wills are determined and constrained by our genes, environments, nutrients, and experiences. The reason I have put this one in the almost certain category is that it is possible that bodies, genes, cells, stars, planets, moons, galaxies, universes may not actually exist. These things could be part of a simulation or dream or hallucination or illusion. It is impossible to know with complete certainty. I could be a solipsistic soul experiencing the illusion of being in a human body on a planet in a universe or I could be a body without any soul - I don't know these things for sure, hence I am an agnostic. There are many hypotheses that can't be tested e.g. simulation hypothesis, illusion hypothesis, dream hypothesis, hallucination hypothesis, solipsism hypothesis, philosophical zombie hypothesis, panpsychism hypothesis, pantheism hypothesis, etc. Just because a hypothesis can't be tested it does not mean it is true or false. It just means that it is currently untestable.

[boatsnguitars]

It's a good list. If only others agreed, we could have a better existence. No war, strife, disease - because we'd get on with the actual business of reality instead of spending all our time and resources on fantasies filled with hatred.

[Compassionist]

It's a good list. If only others agreed, we could have a better existence. No war, strife, disease - because we'd get on with the actual business of reality instead of spending all our time and resources on fantasies filled with hatred.

Thank you. I agree with you.

[elphidium55]

Can I be completely certain of the claim "There is no beer in the frig!"? If I was desperate enough for a beer would it be wrong for me to take a look in the frig? What should I think if I see a shopping list with a checkmark next to the words "buy beer"? If I see a receipt from the grocery store on the kitchen table which includes a charge for a six pack of beer, should I revise my belief? What if the refrigerator door mysteriously falls open and I see it's full of beer? Should I deny what I see right in front of me? Or does my certainty make my no-beer belief unreviseable?

I am sympathetic to what is know as "phenomenological conservatism" (henceforth, PC). PC defends the view that our sensory perceptions about middle sized objects in everyday contexts are broadly reliable. If it looks like a duck and waddles like a duck and quacks like a duck, we have prima facie justification for believing it is a duck (at least in the absence of reasons to the contrary). Such beliefs are defeasible - my credences can be very high or very low without having to be at 0% or 100%.

[bob the baptist]

I am completely certain of the following:

1. I am conscious.
2. I am typing in English.
3. I am not all-knowing.
4. I am not all-powerful.
5. I change.
6. I can't do lots of things I really want to do e.g. go back in time and prevent all suffering, inequality, injustice, and deaths and make all living things forever happy.
7. I do some things even though I don't want to do them. Here are some things I have done, currently do or will do even though I don't want to do them:

1. Breathe
2. Eat
3. Drink
4. Sleep
5. Dream
7. Pee
8. Poo
9. Fart
10. Burp
11. Sneeze
12. Cough
13. Age
14. Get ill
15. Get injured
16. Sweat
17. Cry
18. Suffer
19. Snore
20. Think
21. Feel
22. Choose
23. Be conceived
24. Be born
25. Remember some events that I don't want to remember
26. Forget information that I want to remember
27. Die

I am almost certain of the following:

1. I and all the other organisms currently alive will die. Every second brings all organisms closer to death.
2. My body, other organisms, the Earth and the Universe really exist and they are not part of a simulation or hallucination or dream or illusion.
3. Other organisms e.g. humans, cows, dogs, cats, chickens, pigs, lions, elephants, butterflies, whales, dolphins, etc. are sentient beings who feel pain.
4. Being a non-consumer is more ethical than being an autotroph, being an autotroph is more ethical than being a vegan/herbivore, being a vegan is more ethical than being a vegetarian, and being a vegetarian is more ethical than being an omnivore or carnivore.
5. Gods do not exist.
6. Souls do not exist.
7. Reincarnation does not happen.
8. Resurrection does not happen.
10. Organisms evolved and were not created by God or Gods.
11. 99.9% of all the species to evolve so far on Earth became extinct in 5 mass extinctions long before humans evolved.
12. Humans and other organisms do not have free will. Our wills are determined and constrained by our genes, environments, nutrients, and experiences. The reason I have put this one in the almost certain category is that it is possible that bodies, genes, cells, stars, planets, moons, galaxies, universes may not actually exist. These things could be part of a simulation or dream or hallucination or illusion. It is impossible to know with complete certainty. I could be a solipsistic soul experiencing the illusion of being in a human body on a planet in a universe or I could be a body without any soul - I don't know these things for sure, hence I am an agnostic. There are many hypotheses that can't be tested e.g. simulation hypothesis, illusion hypothesis, dream hypothesis, hallucination hypothesis, solipsism hypothesis, philosophical zombie hypothesis, panpsychism hypothesis, pantheism hypothesis, etc. Just because a hypothesis can't be tested it does not mean it is true or false. It just means that it is currently untestable.

You asked for COMPLETE certainty. Humans can not know anything with complete certainty. i.e. You can not know you are going to die, its just a good bet. If and when you do, you won't know it. But then, as a Christian, I would argue that you will most certainly know it. If I believe it, it is certainty.