To install click the Add extension button. That's it.

The source code for the WIKI 2 extension is being checked by specialists of the Mozilla Foundation, Google, and Apple. You could also do it yourself at any point in time.

Kelly Slayton
Congratulations on this excellent venture… what a great idea!
Alexander Grigorievskiy
I use WIKI 2 every day and almost forgot how the original Wikipedia looks like.
Live Statistics
English Articles
Improved in 24 Hours
Added in 24 Hours
What we do. Every page goes through several hundred of perfecting techniques; in live mode. Quite the same Wikipedia. Just better.

Relation of Ideas

From Wikipedia, the free encyclopedia

In philosophy, a relation is a type of fact that is true or false of two things. For instance, "being taller than" is a relation that is true of "Shaquille O'Neal and Ross Perot" and false of "the Empire State building and Mt. Everest." Substances or things have properties ("this spot is red"). Relations on the other hand obtain between two substances ("this spot is bigger than that spot") or two properties ("this red is a darker shade than that red").

There are two major kinds of relations:[1] ontological and epistemological. Ontological relations are entities like "father", which is a person considered in his relation to a child. Epistemological relations are often logical connections that obtain between two concepts or ideas, like "entailment." The fact that all men are mortal and that Socrates is a man entails that Socrates is mortal—the relation between Socrates' mortality and the mortality of all men is an entailment relation.

YouTube Encyclopedic

  • 1/3
    55 392
    2 228
    35 780
  • ✪ PHILOSOPHY - Epistemology: Hume's Skepticism and Induction, Part 1 [HD]
  • ✪ Mod-01 Lec-18 Hume : Impressions and ideas, knowledge concerning relations of ideas and knowledge
  • ✪ Epistemology: Hume's Skepticism and Induction Part 2


- [Voiceover] My name is Daniel Greco and I'm an assistant professor of philosophy at Yale University. Today's video will concern a topic in epistemology, which is the branch of philosophy that deals with the study of knowledge. In particular, I'll discuss a version of skepticism, which is the idea that we know a lot less than we ordinarily take ourselves to. The sort of skepticism I'll discuss is due to David Hume, who was an 18th century Scottish philosohper and historian, and it targets our knowledge of the unobserved. To get clearer about just what that amounts to, we'll have to start with some examples. So we ordinarily take ourselves to know lots about things that we haven't directly observed. For instance, I take it that I know that blue whales are the largest animals on earth. I bet you know that too. I take it I know that the Alpha Centauri system is the nearest star system to our own. I take it I know that there was a man named Napolean who conquered much of Europe. I also take it I know when the next American presidential election will be. None of these are things that I've directly observed. I haven't seen any blue whales. I certainly haven't seen all other animals on earth to compare them to. I never met Napoleon, and I haven't observed anything in 2016 yet. And yet I, and I take it, you, ordinarily take myself to know all sorts of things about these matters. So how do we know these things about stuff that we haven't yet observed? In some cases it seems pretty easy. For instance, I know that all triangles, even triangles I haven't yet observed, have three sides. Or I know that next year, if I have two apples and two oranges, I'll have four pieces of fruit. What's special about these cases that makes them so easy to know? The way that Hume put it, they express relations of ideas. A relation of ideas is something whose denial is inconceivable, or self-contradictory. Try to imagine a two-sided triangle. I take it you can't do it. Or try to imagine a situation where I have two apples and two oranges and nothing else, but where I don't have four pieces of fruit. Again, I suspect you're gonna have trouble. Here's another way of getting at the same idea. Relations of ideas have to be true, no matter how the world turns out. They're necessary truths. So what does it take to know claims like this? What does it take to know relations of ideas? To quote Hume, he said that propositions of this kind are discoverable by the mere operation of thought, without dependence on what is anywhere existent in the universe. And what does that mean? Why does he think that's true? I take it the idea is something like this. If some claim is a relation of ideas, then it will be true no matter what the world is like. So in order to know that it's true, we don't need to go out and gather evidence about what the world is like. The evidence might tell us the world is this way rather than that way, but no matter what way the world is like, all triangles will have three sides. Two pieces of fruit and another two pieces of fruit will make four pieces of fruit. So if anything at all is required to know that a relation of ideas is true, it's just understanding. This is what Hume called the mere operation of thought. That's enough to see that it has to be true, and so to know that it's true. Okay, contrast relations of ideas with another class of claims that Hume called matters of fact. For example, as I now make this video, it's raining outside. Or here's another one, I have a fluffy puppy. So these claims are true, both of them, but their denials are not inconceivable or contradictory. The mere operation of thought isn't enough to get us knowledge of their truth. You could easily imagine that it's sunny outside. In fact, maybe as you listen to this video, it is. Or you could imagine that I have no pets at all, including no fluffy puppy, even though, in fact, I do. So because these claims have denials that aren't contradictory, because you can conceive that they're false, it's not enough to just understand what they mean to see that they're true. You have to go out and make some observations, see that the world is one way, rather than another way. So these matters of fact contrast with relations of ideas and what it takes to know them. This distinction that Hume is getting at, between relations of ideas and matters of fact, is closely related to what was later called the distinction between the a priori and the a posteriori, by Immanuel Kant.

Relations in modern philosophy

Relation of Ideas, in the Humean sense, is the type of knowledge that can be characterized as arising out of pure conceptual thought and logical operations (in contrast to a Matter of Fact). For instance, in mathematics: 8 x 10 = 80. Or in Logic: All islands are surrounded by water (by definition).

In Kantian philosophy, a relation is equivalent to the analytic a priori. Unlike Hume, Kant denied, in the introduction to his "Critique of Pure Reason", that mathematical truths were analytic.[2] Rather, 'a bachelor is unmarried' is true by relation of the definitions of the concepts of 'bachelor' and 'unmarried.'

In Leibniz, relations of ideas are also similar to the so-called Truths of Reason, which are defined as those statements whose denials are self-contradictory.


  1. ^ J.P. Moreland, Body and Soul, p.?
  2. ^ Immanuel Kant, Critique of Pure Reason, Introduction

This page was last edited on 12 July 2020, at 17:51
Basis of this page is in Wikipedia. Text is available under the CC BY-SA 3.0 Unported License. Non-text media are available under their specified licenses. Wikipedia® is a registered trademark of the Wikimedia Foundation, Inc. WIKI 2 is an independent company and has no affiliation with Wikimedia Foundation.