I'm trying to perform an analysis but I'm unsure which way around the premise and conclusions are.

Here is the example:

``````"The circulatory system is able to circulate blood.".
``````

Now I'm trying to analyze this sentance, and do so using an implication.

``````"The circulatory system is able to circulate blood." IF "The circulatory system is able to move blood." AND "The circulatory system is able to transport blood."
``````

But i'm not sure if the implication is the right way around, should the original sentence be the premise or conclusion of an implication?

Thanks

• There is no implication here. Just a predicate P(x) := "x is able to circulate blood" applied to an individual constant c := "circulatory system", i.e. P(c). Jan 8, 2022 at 12:17
• @Conifold but doesn't the fact that the circulatory system can move and transport blood imply that the circulatory system can circulate blood? Jan 8, 2022 at 12:32
• So you have an analysandum, here, the complete proposition (CIRC) The circulatory system (C) is able to circulate blood. And you're trying to elucidate the meaning with the analysans, (i) C is able to move blood and (ii) C is able to transport blood. You are asserting (I think?) that (i) and (ii) together are necessary and jointly sufficient conditions for CIRC and that the meaning of CIRC can be understood in terms of these truth conditions. Is that accurate? Or are you trying to do something else that I've missed? Jan 8, 2022 at 15:11
• Whatever facts about the circulatory system may imply they are not what the first sentence asserts. Jan 8, 2022 at 15:11
• @AlabamaScholiast Yes this is what i'm trying to do. Jan 8, 2022 at 17:03

So if I've understood you correctly, based on your original question and your replies in comments, then I think the short answer here is that you are constructing a biconditional; so the inference can go, so to speak, both ways.

In your analysis, you say that you have an analysandum, here, the complete proposition:

(C) The circulatory system is able to circulate blood.

And you're trying to elucidate the meaning with the analysans:

1. (M) The circulatory system is able to move blood.
2. (T) The circulatory system is able to transport blood.

And you are asserting (as you indicate in comments) that M and T together are necessary and jointly sufficient conditions for C; the meaning of C can be understood in terms of these truth-conditions.

If so, then the normal way to handle this kind of analysis is to understand it as a sort of definition:

C =df MT

or:

"The circulatory system is able to circulate blood." =df (i) The circulatory system is able to move blood, AND (ii) the circulatory system is able to transport blood.

A definition of a complete proposition like C in terms of other complete propositions would normally be taken to set up a logical equivalence or biconditional -- C is true if and only if (i) M and (ii) T are both true.

C ↔ (MT)

or:

"The circulatory system is able to circulate blood." is true IF AND ONLY IF (i) The circulatory system is able to move blood, AND (ii) the circulatory system is able to transport blood.

(The biconditional is not the same thing as the definition; for a highly technical discussion of the ins and outs see for example Stanford Encyclopedia of Philosophy on "The logic of definitions"; but if the definition is a correct analysis of the proposition, then the biconditional is necessarily true.)

Since this is a logical biconditional (i.e., the conditions on the right-hand side of the double-arrow are necessary conditions; but they are also jointly sufficient conditions), the inference runs, so to speak, in either direction -- the following would be a valid argument:

1. C ↔ (MT) (Pr.)
2. C (Pr.)
3. Therefore, MT (1, 2)

But so would the following:

1. C ↔ (MT) (Pr.)
2. MT (Pr.)
3. Therefore, C (1, 2)

I.e., either side of the biconditional, if taken as a premise, will imply the other side as a conclusion. As a matter of language, the proposition on the left-hand side of a biconditional may sometimes be called the antecedent and the proposition on the right-hand side may sometimes be called the consequent. But because you have the biconditional rather than a simple conditional, either side will imply the other, and vice versa.