The limits of knowledge

• Normal incredulity 


  Normal, everyday doubts about the world we live in. E.g a doubt about whether a mushroom 🍄 is safe to eat
• Philosophical doubt


  Beyond ordinary doubt, uncertainty over everything we know. E.g Are my hands real?
• Infinite regress


  A sequence of reasoning/justification, we can never come to an end with
• Normal incredulity only occurs where there is good reason to doubt a belief. E.g mushrooms

  • You see a mushroom in a field, is it edible?
  • It smells like an ordinary mushroom 🍄 In a shop
  • Deathcap mushrooms also smell like this however, what if it's a poisonous mushroom and not a field mushroom?
• Philosophical doubts are when you are doubting fundamental beliefs about who you are/what exists. E.g. are my hands real? Is everything around me real? 😭
• Theoretical doubt is when a philosopher doubts the truth of a proposition, a what if scenario. Making up and idea 💡 to explain something 😀
• Normal incredulity occurs when we encounter ordinary evidence. Alters our behaviour due to the evidence 🧾 provided. Balanced against a set of other beliefs which are taken for granted as being true. Doubt can be removed with ordinary evidence.
• Philosophical scepticism needs lots of proof to not be doubted, it may be impossible to remove doubt 🧐. It extends to doubting a whole set of beliefs, it has a theoretical rather than practical purpose.
• The infinite regress can be stopped by finding a belief that is true without evidence or supporting reasons, a foundation belief.
• Global sceptic 


  A view that questions the possibility of all knowledge. E.g existence of the external world
• Local sceptic 


  Questions the possibility of knowledge in a particular area of study. E.g. Is Utilitarianism the best way to make moral decisions?
• Local scepticism is the doubt 🤔 of a specific claim or area of knowledge.

  E.g

  • Doubting if we really know how many planets there are in the solar system.
  • Or doubting if an ethical claim such as Kantian ethics is really the best way to live.
• Global scepticism doubts all knowledge, doubting the existence of anything. For example, the brain 🧠 in a vat argument: what if we are not 🚫 walking, talking, human beings but just a brain in a vat controlled by a supercomputer 🖥️, directing everything, even our experiences. We cannot prove whether we really exist or if we are in fact just a brain in vat. 😄
• Reliabilism response to global scepticism: assuming we're not being deceived by and evil demon 👿/ brain 🧠 in a vat. Our perception would count as a reliable method of gaining knowledge because my perceptions could reliably cause me to form beliefs about the world.
• Reliabilists consider two scenarios:

  1. I am not 🚫 a brain in a vat: So, my perception is reliable as I'm living in the real world 🌍 and perceiving it accurately, my perception leads me to believe I have hands. My belief if true because I'm not a brain 🧠 in a vat. So, according to reliabilism I know I have hands
  2. "I am a brain in a vat". My perception isn't reliable, I'm a brain in a vat being fed artificial stimuli, my perception leads to the belief "I have hands". This belief is false, formed through an unreliable method. So, according to this situation you don't know if you have hands 😭
• The point of the reliabalism argument is that in scenario one, we can have knowledge of ordinary propositions such as : I have hands.

  Although we cannot know 😕 if we're in situation one or two and cannot be fully sure we know such propositions, we don't have to. We can know 😜 things without knowing that we know that thing.

  If we're not in a sceptical scenario, then knowledge is possible as knowledge is defined as a true belief formed by a reliable method and our perception is reliable if we're not being deceived so we can know basic propositions such as: I have hands ✋ 👌