The truth of fiveness

Someone in my philosophy class made the statement that they believe the emperical (sense dataum) view of truth is the ultimate view; they made the statement that they agreed with the idea of locke and hume that our minds from birth are a tabula raza (blank slate) – I’m a rationalist (although not purely) and I would agree with Plato & Socrates that there is knowledge that is a priori – even if not seen prima fascie.


The thought is that you can teach your child that 2+2=5; and because they learn through experience, until experience shows them otherwise, they will believe that it is true (does false belief equate to knowledge?). Here is my counter argument. 🙂



I don’t agree with either Locke or Hume that our mind is a blank slate at birth, just like with Socrates, Plato and many other rationalists, I believe there are many things that we know a priori; although I would admit prima fascie it may seem like we are a blank slate.


If your son was told, and thus believed that 2+2=5, would it be true? So if you give him one item, then another item, then another item and another item and present them to him, and ask him how many items he has, would he be able to present you back with 5 items (even though he only had 4?).


Your son may not understand the idea of fiveness, but could he thus produce 5 items out of 4? So while he can’t justifiably know that 2+2=5 without having an experience of fiveness, is there not a standard of fiveness beyond him that can be known a priori (that is 4 != 5)?


But, I also am not a pure rationalist, I agree with you that there are many things that we learn through experience, and not pure rationalization – however, how much can we trust experience without rational thought?


For example, to many people, including myself, 60 is really warm in the winter, but really cold in the summer, so which is true to me, is 60 warm or 60 cold? Experience, in this case would say “It depends”, but rational thought would say “My body is roughly 98 degrees, so 60 degrees is about 38 degrees colder than my body, so 60 is to be perceived as cold”.