Derek Parfit on Non-Religious Ethics

by Luke Muehlhauser on August 21, 2010 in Ethics,Quotes

(Parfit, Reasons and Persons, pg. 454.)

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{ 15 comments… read them below or add one }

Rob August 22, 2010 at 3:18 am
cl August 22, 2010 at 9:32 am

Just a small, seemingly minor criticism:

Since we cannot know how ethics will develop, it is not irrational to have high hope.”

Does not knowing how something will go make it rational to hope in one direction or the other? I think most rationalists would disagree with that.

Anyone?

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James Gray August 22, 2010 at 1:05 pm

cl,

He doesn’t say it is a rational requirement to have high hopes. He says it is merely rational. It is possible to be rational and have low hopes based on what he said.

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cl August 22, 2010 at 1:33 pm

He doesn’t say it is a rational requirement to have high hopes.

I understand. I’m asking how it can be considered “not irrational” to have hope sans knowledge. In my experience, most rationalists mock just that – when the religious do it.

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James Gray August 23, 2010 at 3:04 pm

I don’t think rationalists mock plausible beliefs. It might be that some rationalists don’t think religions are saying plausible things. The teapot argument is a good example. If a belief is too far fetched, then it isn’t rational to believe it.

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cl August 23, 2010 at 4:05 pm

If a belief is too far fetched, then it isn’t rational to believe it.

That’s not a good definition, IMO. Who becomes the arbiter of far-fetchedness? I prefer the simpler definition: if there’s no evidence for X, then it is irrational to believe in X – whether X is God, objective morality, or the sort of moral consensus Parfit hopes for.

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Leon August 24, 2010 at 4:13 pm

Uhhh… in what sense is either mathematics or secular ethics at an early stage? They’re both thousands of years old.

Is his argument something like:

Mathematics has unsure foundations but has been incredibly successful, so

secular ethics, which has unsure foundations, can reasonably be hoped to be successful.

or is it more like:

In the end we all reached agreement about mathematics, so

it can be reasonably hoped we will all reach agreement about secular ethics.

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James Gray August 24, 2010 at 4:30 pm

cl,

I didn’t give a definition of rationality.

I also disagree that we need evidence to rationally believe something. What kind of evidence do you have that induction is a reliable form of evidence? We have pretty much taken such a fact as axiomatic. That’s not to say that there is no reason to agree that induction is reliable, but the reason isn’t necessarily “evidence” because “evidence” itself requires induction.

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James Gray August 24, 2010 at 4:34 pm

Leon,

He said that mathematics is something we have reached agreement about. He never said mathematics was at an early stage. The second argument you suggest sounds more like what he is saying.

I think his argument could use natural science as an example. Early natural science (Aristotle) was clearly wrong but that didn’t imply there was no scientific truth.

Finally,

It’s not clear how non-religious ethics is at an early stage. Such a thing has existed for quite some time. Plato and Aristotle are good examples. I suspect Asia also had secular ethics.

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cl August 28, 2010 at 5:18 pm

James Gray,

Unless you just meant to describe what many rationalists do in practice, you proffered “far-fetchedness” as a criteria for rational. I don’t think that’s a good criteria at all.

I also disagree that we need evidence to rationally believe something.

I’m with you there. I was simply echoing a common rationalist trope.

I just thought Parfit’s statement was odd, that’s all.

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James Gray August 28, 2010 at 6:23 pm

cl,

To believe something that lacks “sufficient justification” is irrational. Far-fetchedness is one reason to disbelieve in something, but it’s just one consideration among others. Far-fetchedness is a good reason to doubt something insofar as it represents a violation of Occam’s Razor. So, if we are unable to discern if something is true or false (there is on reason to rationally prefer one over the other) except it’s far-fetched, then we have good reason to doubt its existence.

Famous uses of “far-fetchness” includes both Russell’s teapot and Mackie’s argument from queerness. The word “far-fetched” might be a bit imprecise, but it can be made precise.

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cl September 4, 2010 at 3:45 pm

if we are unable to discern if something is true or false (there is on reason to rationally prefer one over the other) except it’s far-fetched, then we have good reason to doubt its existence.

I disagree, though I understand that “far-fetchedness” is problematic. My point is, many things that we once thought “far-fetched” clearly were not. Given that fact, don’t you think caution is mandatory? By your logic, we had good reason to doubt that the sun is the center of our solar system. I don’t think that’s accurate.

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James Gray September 4, 2010 at 4:14 pm

I disagree, though I understand that “far-fetchedness” is problematic. My point is, many things that we once thought “far-fetched” clearly were not. Given that fact, don’t you think caution is mandatory? By your logic, we had good reason to doubt that the sun is the center of our solar system. I don’t think that’s accurate.

Occam’s razor was the first reason to prefer the view that the Sun is the center of the solar system. Copernicus’s heliocentric model made it much easier to predict the movement of the planets. It would be more far fetched to think that the universe has planets moving in strange complected patterns than to think they are probably going around a Sun.

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cl September 6, 2010 at 1:54 am

Occam’s razor was the first reason to prefer the view that the Sun is the center of the solar system. Copernicus’s heliocentric model made it much easier to predict the movement of the planets. It would be more far fetched to think that the universe has planets moving in strange complected patterns than to think they are probably going around a Sun.

Of course, but that misses my point entirely: far-fetchedness is inextricably intertwined with human knowledge, and before all that, the truth seemed far-fetched because we were steeped in ignorance. In another few hundred years, at least some of what we would call far-fetched today will be commonplace.

Would you agree or disagree with that?

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James Gray September 6, 2010 at 3:01 am

Of course, but that misses my point entirely: far-fetchedness is inextricably intertwined with human knowledge, and before all that, the truth seemed far-fetched because we were steeped in ignorance. In another few hundred years, at least some of what we would call far-fetched today will be commonplace.

Would you agree or disagree with that?

I already said that far-fetchedness is merely one consideration among others. It isn’t sufficient reason to disbelieve something.

That said, what we should believe is based on the available information we can get, and that does often change. Einstein’s Theory of Relativity wasn’t endorsed until the information confirmed it and that is when it was rational to believe it is true.

Far-fetchedness doesn’t make something false, but it does count as a reason to rationally disbelieve in something. I am talking about rationality — what we should believe based on the available information rather than facts that we might not be able to know about.

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