Bullshit like this is exactly why I think scientists are better philosophers than philosophers are. The text you've quoted, is, frankly, not the writings of an

Bullshit like this is exactly why I think scientists are better philosophers than philosophers are. The text you've quoted, is, frankly, not the writings of an intelligent person. The reason I'm being very blunt about this, is because bullshit like this is actively harmful. Science is fucking important. Science is what resulted in the technology you're using to read this. Science is, with non-negligible probability, the basis of medicine that prevented you from dying before the age of 5 to be able to read this. When philosophers posit that they can inspect the their own navels and find deep truths about the world, they are undermining one of the fundamental pillars of society that holds up so much of the positive changes humans have been able to make. We need to call this what it is--nonsense and misinformation--and stop amplifying its signal. > By ‘Bayesian’ philosophy of science I mean the position that (1) the objective of science is, or should be, to increase our ‘credence’ for true theories, and that (2) the credences held by a rational thinker obey the probability calculus. However, if T is an explanatory theory (e.g. ‘the sun is powered by nuclear fusion’), then its negation ~T (‘the sun is not powered by nuclear fusion’) is not an explanation at all. Therefore, suppose (implausibly, for the sake of argument) that one could quantify ‘the property that science strives to maximise’. If T had an amount q of that, then ~T would have none at all, not 1-q as the probability calculus would require if q were a probability. Of course "the sun is not powered by nuclear fusion" IS an explanation, it's just not an explanation of a phenomenon we observe, which is why most scientists don't believe "the sun is not powered by nuclear fusion". If we observed something about the sun that was not consistent with the hypothesis that it is powered by nuclear fusion, "the sun is not powered by nuclear fusion" would indeed be an explanation of what we were observing. This is all sidestepping the absurdity that Deutsch doesn't seem to understand that "none at all" has a mathematical representation, 0, meaning that if p = 1 - q = 0, then q = 1. This is not difficult math here, folks. > Also, the conjunction (T₁ & T₂) of two mutually inconsistent explanatory theories T₁ and T₂ (such as quantum theory and relativity) is provably false, and therefore has zero probability. Yet it embodies some understanding of the world and is definitely better than nothing. Uh sure, which is why nobody with a brain takes the conjunction of those two things. This isn't a criticism of Bayesian philosophy of science, it's a straw man argument. > Furthermore if we expect, with Popper, that all our best theories of fundamental physics are going to be superseded eventually, and we therefore believe their negations, it is still those false theories, not their true negations, that constitute all our deepest knowledge of physics. Deutsch apparently doesn't know what an approximation is, and instead thinks of correct/incorrect as a binary. Relevant https://hermiene.net/essays-trans/relativity_of_wrong.html https://hermiene.net/essays-trans/relativity_of_wrong.html