“Here is one way to see the problem with Drebin’s theory. To explain the data, we need to fine-tune the theory by assuming that the code that the robbers guessed was the correct code.”
“On naturalism, the existence and fundamental properties of the universe are brute facts.”
”The fine-tuning argument invites us to consider this particular fact about our universe: it supports the complexity required by life forms.”
“Over the last 40 years, physicists have found that the necessary conditions for life are extremely rare among the set of possible universe we are considering.”
“1. We vary the values of the constants in the equations of the laws of nature.“
“2. Similarly, we can vary the initial conditions of the same equations.”
“So, with respect to the ECC, we model our ignorance with a uniform probability distribution.”
“…such "speculation" pre-dates the discovery of the fine-tuning of our universe by a couple of millennia, so one can hardly accuse the theist of ad-hocery,”
When I say that “On naturalism, the existence and fundamental properties of the universe are brute facts", by "universe" I mean the entirety of physical reality. It would include any physical multiverse or universe generator.
On naturalism, the existence and fundamental properties of the universe are brute facts.
Consider Drebin's theory: the robber guessed the code. We are told that there two different hypotheses:H1) that the robber took one guess at the codeH2) that the robber took one guess at the code, and entered the correct code.As far as Bayes theorem is concerned, these are the same hypothesis.
Firstly, the objection proves too much....Now, the objection is trying to argue that an infinite range for a makes p(x|TB) undefined, which makes p(L|TB) undefined. But, for the same reason, p(D|TB) is undefined for any D. We can't calculate the probability of a life-permitting universe because we can't calculate the likelihood of anything. The objection would sink fine-tuning by sinking all the associated theories of physics.
1. There is only one world, the natural world.2. The world evolves according to unbroken patterns, the laws of nature.3. The only reliable way of learning about the world is by observing it.
... recall that Barnes suggests that, on LBN, ECC is a fundamental descriptor of all physical reality ... LBN is the hypothesis that all of physical reality is described, at a fundamental level, by the known laws of nature.
Rather than consider every possible way that a physical universe could be, we will restrict our attention to a well-characterised, as-best-we-know unbiased set of possibilities.
... he is going to "represent his ignorance" by further describing the range of possible values for each of these brute facts with a uniform distribution.
Within our equations, ECC can range between -mPl and +mPl, where mPl is the Planck mass.
with respect to the ECC, we model our ignorance with a uniform probability distribution.
Barnes points out that he actually can choose non-arbitrary upper and lower bounds for ECC. That's fine, but that's just one of the values on which his argument rests. ... Most if not all of the other values in question do not have possible ranges which are bounded by theory.
We do not confine our attention to a tractable problem, and admit that naturalism cannot tell us what physical universe we would expect to exist. No likelihood, no posterior. Naturalism avoids the challenge of fine-tuning by admitting that it is incoherent, and thus cannot be rationally believed.
"Scientists commonly argue for their theories from evidence known long before the theories were introduced. ... Old evidence can in fact confirm new theory, but according to Bayesian kinematics it cannot."
Insisting I use the law of total probability to calculate a number I already know is an unnecessary complication, not a better method.
Now, there are other terms in the expression for p(LSU|N). These are currently unknown. If they are in principle unknowable, then p(LSU|N) is in principle unknowable, and we'll never know whether naturalism is plausible in light of the evidence. On the other hand, if they are knowable but as yet unknown, then we can say is that the best handle we have on the problem tells us that naturalism is extraordinarily improbable. Which is exactly my point.
But wait a moment: why is it up to me to calculate the likelihood of the data on naturalism? Shouldn't the naturalist be champing at the bit to test their ideas against evidence?