HUME 2 SKEPTICISM ABOUT CAUSAL KNOWLEDGE
David Hume 1711 - 1776 This book cannot cause me to see words, but its constant conjunction with seen words causes (?) me to hang on to it.
2 Theses about Causal Knowledge THESIS 1: Knowledge of cause and effect is “based on experience.” THESIS 2: Our causal conclusions “are not founded on reasoning or any process of understanding” based on our experience. (225)
The Inference to Causal Connection THE INFERENCE in causal reasoning: “…we always presume when we see like sensible qualities that they have like secret powers” (225) For example: Aspirin relieved my headaches in the past. So: Aspirin has the power to relieve my headaches.
THE MISSING “MEDIUM” These inferences are invalid as they stand: a premise (medium) is missing. 1. Aspirin relieved my headaches in the past. 2. Missing “Medium” [= middle premise]. So: Aspirin causes headache relief. [=Aspirin always relieves headaches.] Question: What is the missing premise (medium)? (225-6)
THE MISSING “MEDIUM” Answer: “…the future will be conformable to the past.” (226) [= “nature is uniform”] 1. Aspirin relieved my headaches in the past. 2. Nature is uniform. So: Aspirin causes headache relief. [= Aspirin always relieves headaches.]
The Uniformity of Nature 1) Is not known a priori. Whatever is known a priori cannot be false without contradiction, but there is “…no contradiction that the course of nature may change.” (226)
The Uniformity of Nature 2) Is not known a posteriori. that nature has been uniform in the past does not entail that it will be uniform in the future, unless we assume that nature is uniform—and thus argue in a circle. (226R)
AUXILIARY ARGUMENTS 1) Science requires repetition, but logic never does. (226R) 2) Non-logical children and animals have causal knowledge. (227)
Hume’s theory of causal knowledge 1)“CUSTOM OR HABIT” is the basis of causal knowledge (229) 2) NATURE gives us “principles of…association of ideas” (231-2): i) resemblance ii) contiguity in time or place iii) causation