My philosophy brain went to rot years ago, but once upon a time I understood that logic and causality are NOT the same thing. Logic is a discipline of reasoning. It is the foundation of mathematics. It consists largely of deductive reasoning: if-then statements, etc… Causality is, well, a feature of nature. It is a connection between two events in reality. A spark causes a bit of sulfur to burst into flame. As far as I can tell, what usually happens in science and non-philosophical reasoning is that we take a causal relationship and kind of map it onto a logical one. Usually, the causal relationship is transformed into a logical one. Let’s return to the spark and sulfur example. Through experimentation we discover said causal relationship and claim that the spark causes the sulfur to burn. Logically, that breaks down to a two premise argument (followed by a conclusion), something like:
If you have a spark, this sulfur will burn;
We have a spark;
Therefore, this sulfur burns.
Or something like that. As a general rule, the causal relationship maps to the logical relationship of implication. A causes B becomes A implies B. Logically, if you have A, then B necessarily follows. It’s that necessary part that causes issues. It is my belief that causality is never a necessary relationship (and Quantum Mechanics might agree with me, if I knew enough about it). In logic, the implication relationship is necessary. It NEVER fails. In nature, are we ever really sure that even our most presumed causal connections are necessary? I think most philosophers would say no. And most scientists would ignore them and go about building marvels that suit us fine.
To look at this differently, the logic relationship deals with the meaning of the words or concepts involved. The causal relationship deals with some kind of connection between two events in the real world… I think. Like I said my philosophy brain has gone to rot.
The upshot of all this is that logic connections and causal connections are two different animals. This is usually most apparent when one looks at what is possible and what is impossible according to each. In logic, a contradiction is impossible, but that’s about it: You can’t have a Euclidean round square. In causality, I think contradictions are also impossible, or, at least, we want them to be—otherwise everything falls apart, even though the behavior of photons and subatomic particles might be threatening to the Law of Non-contradiction. I’m not sure: Remember, I only know a few spattering tidbits about Quantum Mechanics—anyway, the more important point is that there are more impossible things in causality than just contradictions (actually, rereading this, I’m not sure of this; it may be that everything in causal analysis is set up to “echo” logical analysis such that events that contradict well-established “Laws” are deemed impossible). Like, ignoring the Law of Gravity is supposed to be impossible. Not so, in logic. The test in logic, as far as I know, is basically imagination. If you can think it, it is logically possible. Not so with causality. A three-headed pink unicorn is logically possible, but, probably, causally impossible. Another, perhaps more certain example, and this may seem strange to some, the claim that “Socrates can jump unassisted to the moon,” is logically possible, but, most probably, causally impossible.
So, why have logic or study it?
I think I answered that already: logic is the basis of mathematics and without mathematics you really can’t do causal analysis (science). Further, if you are looking for certainty in anything, you are going to have to tread through logical analysis. I know I’m not omniscient; beyond that, I’m not certain about much. Anyway, I think I’ve babbled enough.