Philosophical evidence for evolution?

It isn’t very nice to hoist people—even poseurs—by their own petards.

I have.

Unfortunately, vivisection is the scientific method I use for everything (including my researches in sociology, geology and computer science), and generalizing the results to wider population, while not impossible, always makes it . . . difficult to concentrate . . .

If by philosophy you mean logical argument, and by science you mean creating and testing hypotheses by experiment, you may have philosophical evidence for evolution, but just as much against it. For 2,000 years or so the philosophical method was tried, and very little progress was made. For just over 500 year science has been tried, and we’ve gone to the moon.

As for evolution, it is quite simple, as others have said. Through mutation, diversity is introduced to the genome. Through sexual reproduction, diversity is spread throughout the genome. Through natural selection, simply those with genes that help them thrive in a given environment tend to reproduce more often than those with genes that don’t help, genes encouraging survival predominate. When populations are isolated, this can happen more quickly. And, when changes between two subpopulations cause interbreeding to be impossible or unproductive, the populations diverge. You can spend a lot of time learning the details, but you don’t have to to accept evolution.

  1. Genetic changes occur - If this were not true, all humans would look the same, with the same hair color, skin color, eye color, height, etc.

  2. These differences make it more likely for some to survive hard times than others. - This is somewhat hard to comprehend because we live in times when anybody, no matter their physical handicap, is as likely to live to be 70 as any pro athelete. However, when times are really tough, and food is really scarce, then, for example, an animal that eats leaves is more likely to survive tough times if he has a longer neck that allows him to reach higher in trees than his short-necked cousins.

Add #1 and #2 together and you have evolution. Mix for millions of years and you have all of the genetic variation that we see today.

The only argument that one could logically make to these 2 points is to dispute the “millions of years” part. And the only reason to dispute this is because of a literal interpretation of the Bible. In which case I would point out that for the story of Noah’s Ark to be at all plausible, evolution would have to have worked way faster than we see it working today (since the story only becomes slightly more plausible if Noah only had to take 1 pair of felines onboard, as opposed to a pair of lions, a pair of tigers, a pair of cougars, a pair of panthers, a pair of Siamese cats, a pair of tabbys, a pair of… etc.)

Most creationists believe the universe is only 6000 years old. Evolution doesn’t work in that short a timespan. If you accept the age of the Earth, it follows naturally that species change over such a long period of time.

Here’s a philosophical argument:
Nietzsche said “What doesn’t kill us makes us stronger.”
Evolution is what happens when you replace “us” with “the species” and “stronger” with “better”

I think it depends on what you mean by ‘evolution’. Do you mean simply adaptive changes leading to differential fitness? That’s simple. Do you mean Darwinian biological evolution by natural selection? That’s a little harder. Do you mean the modern evolutionary synthesis? That’s complicated.

But I think the argument should start with reviewing the purely logical basis of evolution as a generative mechanism for diversity, before coming to the concrete, biological or otherwise, realisations of these ideas.

To this end, a simple observation is that if you have something that replicates, some mechanism for change, for variation within the replicator, and some mechanism for selection based on outward (phenotypic) differences introduced by that change, then evolution is not something that may happen, but something that must. It’s not optional. It’s often said that a competition for resources in one way or another is also essential, but it’s in fact more of an accelerant.

Any given object that is, through some means, copied with less than perfect accuracy (replication and variation), and copied more or less well depending on its form (differential selection), will suffice.

Take a joke. Jokes are heard, remembered, and re-told: they’re copied. Human memory isn’t perfect: there will be variation. We are able to remember certain things more easily than others: there will be selection.

So I tell you a joke. You may remember it, and tell it to somebody else; or you might not. Similarly, anybody you tell it to might either remember it, or not. If you remember it, you may remember it less than perfectly – the joke mutates. The same goes for anybody else re-telling the joke.

Now it might happen that, in the course of these mutations, the joke assumes a form that is more easily remembered – perhaps a shorter version, or some that plays on some ingrained cultural knowledge, or something with a particular rhythm or meter develops. If this joke is told to somebody, he is then more likely to be able to recall and re-tell it. Compared to the original joke, this form has a higher differential fitness – say if the original is re-told by one out of five of its hearers, maybe the knew one is recalled by one out of three. Thus, the joke ‘demographics’ will begin to change: the amount of copies of the original in circulation will grow more slowly than the amount of copies of the mutated version. Eventually, thus, the mutated version will outcompete the original one.

This is, essentially, all that there is to the ‘philosophical’ underpinnings of evolution. It’s got nothing to do with biology, or with life – it’s a simple fact of how information gets copied. Life, at bottom, is information coded in genes; this information is copied with variations introduced by mutation, and these mutations then influence the genes’ capacity to be copied. All the rest is essentially elaboration on this basic idea.

One simple elaboration to introduce is competition: there exists some finite amount of resources the replicators need for successful self-replication. In the joke example, maybe one can only recall one particular version of the joke, which is more likely to be the one that’s easier to remember (there would be no point in remembering both). The two jokes then compete for memory space, and on average, whenever the two ‘meet’, i.e. are told to a single person, the original joke is forgotten. So in the long term limit, the new joke not only matches and exceeds the original’s distribution, as a consequence, the original joke becomes less and less prevalent – it ‘dies out’.

These ideas, together, explain the core of Darwin’s original idea of evolution by natural selection: animals reproduce, mutate, are better (or worse) adapted to the environment, allowing them to more (or less) efficiently acquire necessary resources, which leads to higher (or lower) reproduction rates, which leads to one particular variation winning out over others.

The modern theory has more twists and turns – parts of which, like genetic drift, may be controversial (in their role, not their existence), but the whole edifice is rock solid.

This is, in fact, the great fallacy of creationists (well, one of them, at any rate): they take a look at the complex, diverse, and partially controversial modern theory, and think that attacking one part of it amounts to destroying the whole structure. That since a particular theory may be unable to explain the bacterial flagellum, or the mammalian eye, the whole idea of evolution must be wrong. But that’s simply not so.

The strength of evolution is the simplicity of its core idea: imperfect replication leads to differential replication rates, which leads to population diversity. Whether or not some particular evolutionary history of some particular phenotypic characteristic is literally correct is immaterial, and attacking evolution on this basis is missing the point. The simple fact is, if the conditions are right, evolution will occur; this much is not in dispute. The only question could be whether in fact the conditions are right, and this is where empirical support comes in: life replicates; genes mutate; replication speeds and fitness changes – these are the data that an attack on evolution would have to refute. And to my knowledge, no creationist has as yet been able to explain away the triad of bacteria becoming resistant to antibiotics, the existence of ring species, and endogenous retroviruses.

Putting the whole of known reality to one side and just speculating philosophically:

1/ Anything that happens to create copies of itself will (as a pattern, if not physically) tend to endure despite forces that might otherwise destroy any given copy.

2/ This endurance will continue for as long as succeeding copies of the pattern continue to make copies of themselves.

3/ If anything makes imprecise copies of itself, the imprecise copies either will or will not make copies of themselves and thus will either endure as a (slightly different) pattern, or not.

4/ At each imprecise iteration, there is a possibility that the imprecise copy will be more complicated, yet still be something that makes a copy of itself.

Consequently in any reality in which through random processes a thing *could *come to exist that makes copies of itself, the outcome one would eventually expect is for such things *to *exist and to endure for at least some time.

Further, in any reality in which through random processes a thing could come to exist that makes *imprecise *copies of itself, over iterations one would expect a variety of such things - of varying similarity and disparity, and some of significant complexity - to exist and endure.

And this is also what, as it happens, we do find.

Evolution is an empirical fact about life on our planet.
If you frame the discussion in purely philosophical terms, you’ll lose the “debate”, as many find evolution counter-intuitive and it remains quite misunderstood*.

I find it simpler just to establish that it is “real science” and the theory can be used to make predictions.
It has predicted that we would find fossils of countless “missing links” that we subsequently found, it’s predicted the degree of genetic and internal physiological similarity between species, antibody resistence etc.

  • e.g. I was just yesterday talking about neuroscience with a (Cambridge-educated) friend. He pointed out that “obviously” all organisms have within them the desire to reproduce themselves.
    I pointed out that this is only true in an abstract sense, and while things like courting and mating behaviours may be selected for, that doesn’t mean the individual organism knows why it is doing those things.
    He replied that “Well, it’s buried deep in the subconscious…” :smack:

I’m talking about ‘evolution as a parable’ not ‘evolution as a theory’. As such it would have a end goal in agreement with scriptures.

BTW, here’s what talkorigins has to say about this: [

](Evolution and Philosophy: Metaphysics)
There is a “Journal of Evolutionary Philosophy” (a website, really, not a scietific journal) but they seem to be more interested in the philosophical implications of evolution, not a philosophical basis for it.

Note that while I quoted Nietzsche as a basis for a philosophical view on evolution, Nietzsche’s actual views on the matter were much more metaphysical than mine - the whole idea of Kunsttrieb as an embodiment of will-to-power is all a bit woo, actually. There is no universal Werden, and it’s just Romantic vitalism to say otherwise.

I agree with the others that have said you can’t really do this without talking about science. lack of knowledge/familiarity of science, or its outright rejection, is the reason most creationism exists.

If you start out as a creationist and perform unbiased science (assuming the study context is biological diversity etc), you end up describing evolution. That’s how individuals reject creationism, that’s how religious bodies have moved toward acceptance of creationism - that’s how the theory of evolution itself arose.
Honest, intelligent creationists + facts = evolution.

Well and good, but that is not “philosophical evidence for evolution,” it is employment of the concept of “evolution” for a kinda-philosophical rhetorical purpose. Nothing wrong with that, but not what the OP asked for.

That is also how Charles Darwin lost his faith – not just in Genesis, but in God and Christianity as such.

That is what creationists most fear from the theory evolution.

But, could there even be a “philosophical” theory of evolution without such a vitalist concept?

Is that a philosophical approach? Or is it what scientists would call a “thought experiment”? (Yes, of course there’s a difference. The Allegory of the Cave is not a thought experiment,)

Just noticed: Graped word should read ‘evolution’, obviously.

Perhaps not, but it may be a better approach to reach the type of person the OP is trying to.

The point is to “explain and defend evolution to a creationist that has little to no knowledge or interest in science.” Your way might reach the creationist – but reach him with a completely different message.

True, but I think the science part only comes in at the point where one asks: “Does evolution apply to the real world, i.e. does it explain the observed diversity of life?”, not when the question is: “Does evolution work?/Is evolution possible?” Often enough, this is what is being denied by creationists, but this question can be answered on a wholly abstract level, by appealing to arguments like the ones Princhester or myself gave earlier, the conclusion of which is essentially that under certain conditions, evolution is a necessary consequence. This refines the scientific question to be asked to: “Do these conditions exist in nature?”, which I think is far more readily demonstrated than the somewhat muddled question of whether evolution applies to the world.