By the nature of Deutsch and Popper’s ideas being abstract, this essay will also necessarily be abstract. To combat this, let me ground the whole essay in a concrete empirical bet: Popper’s ideas about epistemology, and David Deutsch’s extensions of them, will forever remain in the footnotes of the history of philosophy. Popper’s falsificationism, which was the main idea that he’s widely known for today, will continue to remain the only thing that he’s widely known for. The frustrating fact that Wittgenstein is widely regarded as a more influential philosopher than Popper will continue to remain true. Critical rationalism will never be widely recognized as the “one correct epistemology,” as the actual explanation (or even the precursor to an explanation) of knowledge, progress, and creativity. Instead it will be viewed, like many philosophical schools before it, as a useful and ambitious project that ultimately failed. In other words, critical rationalism is a kind of philosophical deadend: the Deutschian deadend.
- Kasra in the Deutschian Deadend
There are many things you can directly observe, and which are “manifestly true” to you: what you’re wearing at the moment, which room of your house you’re in, whether the sun has set yet, whether you are running out of breath, whether your parents are alive, whether you feel a piercing pain in your back, whether you feel warmth in your palms—and so on and so forth. These are not perfectly certain absolute truths about reality, and there’s always more to know about them—but it is silly to claim that we have absolutely no claim on their truth either. I also think there are even such “obvious truths” in the realm of science—like the claim that the earth is not flat, that your body is made of cells, and that everyday objects follow predictable laws of motion.
- Kasra in the Deutschian Deadend
Deutsch writes:
Some philosophical arguments, including the argument against solipsism, are far more compelling than any scientific argument. Indeed, every scientific argument assumes the falsity not only of solipsism, but also of other philosophical theories including any number of variants of solipsism that might contradict specific parts of the scientific argument.
There are two different mistakes happening here.
First, what Deutsch is doing is assuming a strict logical dependency between any one piece of our knowledge and every other piece of it. He says that our knowledge of science (say, of astrophysics) implicitly relies on other philosophical arguments about solipsism, epistemology, and metaphysics. But anyone who has thought about the difference between philosophy and science recognizes that in practice they can be studied and argued about independently. We can make progress on our understanding of celestial mechanics without making any crucial assumption about metaphysics. We can make progress studying neurons without solving the hard problem of consciousness or the question of free will.
- Kasra in the Deutschian Deadend, quoting Deutsch on Solipsism
At that time I learnt from Popper that it was not scientifically disgraceful to have one's hypothesis falsified. That was the best news I had had for a long time. I was persuaded by Popper, in fact, to formulate my electrical hypotheses of excitatory and inhibitory synaptic transmission so precisely and rigorously that they invited falsification - and, in fact, that is what happened to them a few years later, very largely by my colleagues and myself, when in 1951 we started to do intra- cellular recording from motoneurones. Thanks to my tutelage by Popper, I was able to accept joyfully this death of the brain-child which I had nurtured for nearly two decades and was immediately able to contribute as much as I could to the chemical transmission story which was the Dale and Loewi brain-child.
- John C. Eccles on Popper, All Life is Problem Solving, p.12
In order to state the problem more clearly, I should like to reformulate it as follows.
We may distinguish here between three types of theory.
First, logical and mathematical theories.
Second, empirical and scientific theories.
Third, philosophical or metaphysical theories.
-Popper on the "hierarchy of reliability", C&R p.266
Special Guest: Kasra.
