Do you really 'know' anything?

Question

We can't predict anything because all our reasoning about the external world is based on experience.

We think the sun will rise tomorrow because it always has.
Well, we say we know it.
That's inductive reasoning, to test something and if it happens enough times we assume it always shall. That's the basis of all our science.

But Hume said we can't know anything like this for the following reason.

If we believe that the sun will rise again tomorrow, we believe it based on the argument that "it always has".
"It always has" is based on the supposition that nature is uniform.

So where is the proof for nature being uniform?
The only valid argument for that is "it always has".

So the theory attempts to prove itself, thus making itself cyclic and therefore obsolete.

Answer 1

No. Not for certain. But we all have to go ahead on the best evidence we have, without ever being absolutely certain that it is right.

Answer 2

Yes.

I know that I exist.

Everything else is inferred to some level as you point out.

However. the sun has come over the horizon (Or the Earth has moved under the sun, for the pedants out there) every day for the last 4.5 billion years or so.

All known science (Or at least the science that i think is known) says that it will continue to do so for billions of years.

Do I know that it definitely, absolutely, positively will appear tomorrow morning? No I do not. However past experience says that it is a near unity probability that it will. Will you bet $1,000 against me by claiming that it will not? I will even give you 100:1 odds. Still no? How boring of you to assume that the universe is so uniform!


The proof for nature being uniform is that nature has been uniform up to now. In fact nature is not uniform, but actually quite random, but you have to get down to the quantum level to notice it.

The theory makes no attempt to prove itself. It does make an assumption that the universe will continue to work as it always has.

As long as the theory continues to make correct predictions then it is valid.

Let me know when the macroscopic universe stops being uniform and I will let the scientists know that they need to come up with a new methodology.


As a final note. Philosophy is all well and good and you can have some interesting thought experiments. Just remember that much of it is just mental 'auto-erotica' and bears little to no relevance to the real universe.

Answer 3

I have often said, though not here, that faith is the most important aspect of our lives. Most people misconstrue this to mean religious faith, and nothing could be further from the truth. What I'm really talking about deals with the point you touch on here. We must accept on faith certain basic underpinnings of our reality, such as ( to cite your example) the sun rising tomorrow or gravity continuing to function as normal. If we accept, or at least acknowledge this, then it is not so much a matter of "knowing." Rather, it becomes being able to make predictions of probability based on previous data. Science itself acknowledges this through use of scientific theory.

I would add in closing that it is possible to know some things. For example, I know that is a cute picture of you.

Answer 4

If that is true, then let's make a bet. If the sun rises tomorrow you pay me $1000. If it doesn't, I'll pay you $999999999999999.

I wonder if Hume would pass up a sweet deal like that?

Note: "rise" in the common sense of the term, from the perspective of the Earth observer, not a fictitious lunar colony or something. The location must be well outside the arctic circle on the surface of the planet earth. Void where prohibited.

Answer 5

Not so.

We know that the sun will rise tomorrow because we understand the mechanics behind the earth's rotation, and there is nothing which would cause it to cease. Once we have true scientific understanding, faith in the uniformity of nature is not required.

Hume was an empiricist, and pure empiricism isn't a viable philosophy. It eventually just dissolves into solipsism.

Answer 6

Philosophically, I suppose you have an argument. Practically speaking, I think I'll continue to trust the results of scientific investigation.

I used to subscribe to CSICOP's journal "The Skeptical Inquirer". There was a rather lengthy debate in their letter column between working scientists and "philosophers of science". The philosophers took pretty much the stance you've just enunciated. The scientists pointed out that, if that were true, science couldn't possibly proceed and they had wasted their lives. It's really a matter of Weltanschauung. I side with the scientists.

Answer 7

Yes, yes, we're all probably just submerged in some VR tank while the machines rule the Earth, too.

We know nothing beyond what our senses tell us. We can make some intelligent guesses, though.

Answer 8

True, but in the real world we have to go by the practical rule of thumb that what we observe is probably true, or we wouldn't have a reason to get out of bed in the morning.

Answer 9

logic tells us it will though sweetie
for the sun not to come up tomorrow ... the world would have to stop turning
if it did that ... we would be in more trouble than the sun simply not coming up
so yes , I think I can safely say ..... I know the sun will come up tomorrow

Answer 10

I know that if the sun didn't happen to rise tomorrow, I'd be even colder and not very happy.