Principle of Sufficient Reason (PSR)

The Principle of Sufficient Reason is a powerful and controversial philosophical principle stipulating that everything must have a reason or cause. This simple demand for thoroughgoing intelligibility yields some of the boldest and most challenging theses in the history of metaphysics and epistemology. In this entry we begin with explaining the Principle, and then turn to the history of the debates around it.

Principle of Sufficient Reason

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A Minimal Materialism

From Victor Reppert:

I am convinced that a broadly materialist view of the world must possess three essential features.

First, for a worldview to be materialistic, there must be a mechanistic base level.
Second, the level of basic physics must be causally closed.
Third, whatever is not physical, at least if it is in space and time, must supervene on the physical.

This understanding of a broadly materialistic worldview is not a tendentiously defined form of reductionism; it is what most people who would regard themselves as being in the broadly materialist camp would agree with, a sort of “minimal materialism.”

To the atheists:

Some of you know you’re materialists, some of you suspect it, others try to deny it or don’t like to be identified as such. But if you’re an atheist what else do you have?

Jonathan Bartlett’s “open-ended loop” argument

In the “Evolving complex features” thread, TristanM asks:

I’m curious what the group’s thoughts are on Jonathan Bartlett’s (AKA “JohnnyB”) argument about open-loops in the AVIDA program?

I haven’t studied Jon’s argument yet, but I think some of you have. What did you think?

Why I Love AVIDA – Detecting Design in Digital Organisms

Thoughts on Parameterized vs. Open-Ended Evolution and the Production of Variability

Irreducible Complexity and Relative Irreducible Complexity: Foundations and Applications


Just out of interest … this word gets bandied about a lot, mainly by evolution opponents hereabouts. They seem to use it when a word with multiple meanings is used. The accusation tends not to be withdrawn even when the intended meaning is unequivocally clarified – a bizarre situation where someone commits to a meaning and is still equivocating!

A typical definition is “The use of ambiguous language to conceal the truth or to avoid committing oneself”. There is a veiled hint of dishonesty – making an honest mistake with alternative definitions of a word is not strictly equivocation as defined there. That is, it is not merely ‘using ambiguous language’, still less ‘confusing two definitions of one word’, but purposefully being vague or misleading. But the use of the word rarely seems appropriate to me in the contexts in which it is used – generally, even the charge of ambiguity is unjustified, let alone nefarious motive. Numerous derails are provoked when one party says ‘you are equivocating’ and the other says ‘no I’m not’. I almost invariably find myself siding with (or being) the ‘no I’m not’ party (or, for self-referential funzies, “maybe I am, maybe I’m not”!).

Is this a quirk of American English (Americans forming the majority of opponents in these discussions)? Or is it a meme that has been unconsciously passed from one to another among the evolution-skeptical fraternity? Or something else?

Baby or Vat?

Zachriel asks, at UD:

Here’s a simple thought-experiment. There’s a fire at an fertility clinic, and there is precious little time before the entire building is engulfed in flames. Down one hallway, there’s the soft purring sound of an incubator with a thousand frozen embryos; down the other hallway, the cries of a newborn baby. Which do you choose to save?

Usually, people answer “the baby” and the interesting debate then concerns why.

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Evolving complex features

The Lenski et al 2003 paper, The evolutionary origin of complex features, is really worth reading.  Here’s the abstract:

A long-standing challenge to evolutionary theory has been whether it can explain the origin of complex organismal features. We examined this issue using digital organisms—computer programs that self-replicate, mutate, compete and evolve. Populations of digital organisms often evolved the ability to perform complex logic functions requiring the coordinated execution of many genomic instructions. Complex functions evolved by building on simpler functions that had evolved earlier, provided that these were also selectively favoured. However, no particular intermediate stage was essential for evolving complex functions. The first genotypes able to perform complex functions differed from their non-performing parents by only one or two mutations, but differed from the ancestor by many mutations that were also crucial to the new functions. In some cases, mutations that were deleterious when they appeared served as stepping-stones in the evolution of complex features. These findings show how complex functions can originate by random mutation and natural selection.

The thing about a computer instantiation of evolution like AVIDA is that you can check back every lineage and examine the fitness of all precursors.  Not only that, but you can choose your own environment, and how much selecting it does.  There are some really key findings:

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The Cosmological Argument

I am currently working my way through the book A Natural History of Natural Theology: The Cognitive Science of Theology and Philosophy of Religion.

There is already a thread here dedicated to the book, but I decided to separate the thesis of the book from the actual natural theological arguments themselves. The evidence that the premises upon which these natural theological arguments rest are natural and intuitive are the subject of that thread.

In this thread I’d like to explore how the cosmological argument for the existence of God is presented in the book and provide a place where these cosmological arguments can be examined and criticized.

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Natural Selection and Adaptation

Cornelius Hunter seems very confused.

 …This brings us back to the UC Berkeley “Understanding Evolution” website. It abuses science in its utterly unfounded claim that “natural selection can produce amazing adaptations.”

In fact natural selection, even at its best, does not “produce” anything. Natural selection does not and cannot influence the construction of any adaptations, amazing or not. If a mutation occurs which improves differential reproduction, then it propagates into future generations. Natural selection is simply the name given to that process. It selects for survival that which already exists. Natural selection has no role in the mutation event. It does not induce mutations, helpful or otherwise, to occur. According to evolutionary theory every single mutation, leading to every single species, is a random event with respect to need.

He has forgotten what “adaptation” means.  Of course he is correct that “Natural selection is simply the name given to [differential reproduction]”.  And that (as far as we know), “every single mutation …is a random event with respect to need”.

And “adaptation” is the name we give to variants that are preferentially reproduced. So while he would be correct to say that “natural selection” is NOT the name we give to “mutation” (duh); it IS the name we give to the very process that SELECTS those mutations that promote reproduction.  i.e. the process that produces adaptation.

Cornelius should spend more time at the Understanding Evolution website.

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