is vs. ought - forward vs. backwards chains of reason

[premjan]

Sorry if this is hopelessly vague or misnamed - a lot of human endeavor can be divided between these two opposing tendencies.

It seems that ought starts with an ideal and reasons forward to what is needed to achieve that ideal. Is starts with what is facile or efficient to achieve and then proceeds to reason about the principles that are needed.

Deductive logic is an example of the reasoning forward, whereas induction is an example of reasoning backward. Mathematical proof is again forward reasoning, but in mathematics generally results precede proofs. Results are obtained by serendipity - is reasoning, suspicions, sudden insights etc.

Philosophy is about is, whereas law is about ought. Though case law is about is rather than ought and religion as a branch of philosophy tends to be about the ought.

Science is about is whereas engineering is a bit more about the ought.

And so on - illuminate this distinction further please.

[Chris Porter]

Well, I've noticed that I do both forward and backward reasoning. I think this is because I often think in pictures, and pictures are groups of already "existing" objects to think about, both origin (what the parts were composed from) and toward the future (what new parts can be added).

For example, I generally spot fallacies by 'sense of uneasyness', and then look at the arguement and try to construct it backwards to see why the result makes me uneasy. So the initial step is either using induction or intuition, the next steps are deductive, to the best of my ability, anyway.

It's also why I think art and science are so interconnected--they both seek to explore and explain the "is", while the applied crafts and engineering, seek to construct values from the art and science.

[kennethamy]

Sorry if this is hopelessly vague or misnamed - a lot of human endeavor can be divided between these two opposing tendencies.

It seems that ought starts with an ideal and reasons forward to what is needed to achieve that ideal. Is starts with what is facile or efficient to achieve and then proceeds to reason about the principles that are needed.

Deductive logic is an example of the reasoning forward, whereas induction is an example of reasoning backward. Mathematical proof is again forward reasoning, but in mathematics generally results precede proofs. Results are obtained by serendipity - is reasoning, suspicions, sudden insights etc.

Philosophy is about is, whereas law is about ought. Though case law is about is rather than ought and religion as a branch of philosophy tends to be about the ought.

Science is about is whereas engineering is a bit more about the ought.

And so on - illuminate this distinction further please.

I don't see why deduction is reasoning forward, and induction is reasoning backward. I think that in some cases one has to reason backward to solve some problems (as in reverse engineering). But I don't understand why that is inductive reasoning. But perhaps you have a theory of inductive reasoning I am unfamiliar with.

[premjan]

Deduction reasons from premises to conclusions (forward in the conventional way of writing it). Induction reasons from particulars to generals. Not sure if that is "backwards" but that is the opposite direction of deduction.

[premjan]

computer graphics vs. computer vision is another example.