Through our reading of the literature on Jungian typology, both online and offline, we have seen at least three popular actors in the field propose the idea that “Te is Deductive and Ti is Inductive.” Our argument is as follows: (1) Neither of those functions can be reduced to being merely deductive or inductive, but doing so can still be worthwhile as an exercise that points towards the ultimate nature of each function. (2) Even with this reservation in mind, Ti is deductive while Te is inductive.
We will now argue these claims.
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First, we look at some cursory definitions of Te and Ti as cognitive processes:
Te: Starts with the facts, then moves to the theory, then ends with the facts.
Ti: Starts with the theory, then moves to the facts, then ends with the theory.
Next, let’s look at the definitions of deduction and induction:
Deduction: Starts with the theory, then moves towards the facts.
Induction: Starts with the facts, then moves towards the theory.
So we see that neither Te nor Ti can be made to fit 100% with either deductive or inductive reasoning. Both functions are more complex than simple epithets like inductive or deductive.
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But don’t take our word for it. Here is what Jung said about Te and Ti:
“External facts are not the aim and origin of [Ti]. … [Ti] formulates questions and creates theories, it opens up new prospects and insights, but with regard to facts its attitude is one of reserve. They are all very well as illustrative examples, but they must not be allowed to predominate. Facts are collected as evidence for a theory, never for their own sake. If ever this happens, it is merely a concession to the extraverted style.” (Psychological Types §628)
Bam. After this last sentence, it is hard to argue that Te should be more deductive than Ti.
Likewise, here is what Myers said about Te and Ti:
Te: “Relies on fact … depends upon the facts of experience … has a tendency to multiply facts.”
Ti: “Values facts chiefly as illustrative proofs of the idea … neglect[s] facts … coerce[s] them into agreement with the idea.”
(Both definitions are from Gifts Differing, chapter 8.)
So you see, Myers and Jung are in agreement: In Te, we have a greater preoccupation with the facts, while in Ti, we have a greater preoccupation with the theory.
With deductive reasoning, the overall theory determines the facts, whereas with inductive reasoning the overall facts determine the theory.
Deductive reasoning stresses the theory and neglects the facts that don’t fit, as does Ti.
Inductive reasoning stresses the facts and neglects the facets of the theory that do not fit, as does Te.
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In the end, neither Jung nor Myers nor any of the other classical authors ever used the words ‘inductive’ and ‘deductive’ to make sense of Ti and Te. So maybe the argument will go on forever. But that doesn’t mean that the two lines of argument are equally cogent.
The problem appears to be that people learned in school that induction is ‘wrong,’ and so everyone wants their function to be the deductive one. However, while Induction may be ‘wrong’ in science, our lives would be vastly inefficient if we were to be deductive all the time.
Induction is efficient. It provides support for a conclusion without guaranteeing its ultimate truth. And in the real world, that is often enough. For example, if a bunch of business leaders are sitting around a table, deciding whether to launch a product, they have to use inductive reasoning: “We believe that this product will sell because similar products have sold in the past.” (Or the scientific equivalent: “I believe that the next swan that I see will be white, because almost all swans are white.”) If these business leaders used deductive reasoning, they would never get anywhere!
So there is nothing ‘wrong’ with inductive reasoning as long as one keeps scientific truth out of the question.
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So that is our argument as to why Te is inductive and Ti is deductive. As we said, the functions are more complex than just these simple words, and our argument does in no way mean to say that actual people who prefer to reason by way of Te can’t use deductive logic when the situation calls for it, just as we are not saying that Ti users can’t use inductive logic when the situation calls for it.
On average, however, there is some connection to the overall point in so far as TJ types are more likely to “leave theoretical nuances on the table” as they pursue the facts, while TP types are more likely to “leave facts on the table” as they pursue the theory.
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Update: As John says in the comments below, there are some alternative definitions of deductive and inductive reasoning besides the classical one we cited above. Let’s look at those other definitions. Here are some different examples from a modern textbook:
Inductive Reasoning:
- The window of my house is broken.
- There are footprints in my house.
- My valuables and electronics are missing.
- Therefore, someone broke into my house.
This example is actually much the same as the classical definition of inductive reasoning that we gave above. One starts with the facts, and then moves towards the theory. We also clearly see here how the manner of reasoning is a multiplication of facts (i.e. an extrapolation from facts) and we know from Myers that Te reasons by the multiplications of facts. Thus, in this example, inductive reasoning is still more reminiscent of Te, even though a person who used Ti would probably conclude the same thing. The difference is not so much one of logic, as it is one of psychology: On average, a Te user would be more certain of the inductive conclusion that someone robbed the house than the Ti user would. For as Jung said, external facts are “not the aim” of Ti, and so the Ti user is less comfortable with this type of reasoning as it pertains to the outer world.
Next example.
Deductive Reasoning:
- A woman was murdered in her bedroom.
- If John was seen at the ballgame at the time of the murder, John cannot be the murderer.
- John was seen at the ballgame.
- Therefore, John is not the murderer.
Here we see a line of reasoning that is based on what follows logically from the premises. It is still deduction because the line of reasoning is not so much concerned with the facts as it is concerned with establishing a logical relation between the facts. In the burglar example above, even if 1, 2, and 3 are correct, 4 might still be wrong. In the ballgame example, if 1, 2, and 3 are correct, then 4 must be right. There is no guesswork or multiplication of facts involved.
However, while it would be nice to be able to peg this example to either Te or Ti, we don’t think that such an attribution is possible. In this example, we think the line of reasoning is simply logical, and whether the person reasoning has a preference for Te or Ti will be of minor importance here.
Now for a final example.
Deductive Reasoning:
- All men are mortal.
- Obama is a man.
- Therefore, Obama is mortal.
Here we have an example of hierarchical reasoning. What is true for the higher level of organization (“man”) must be true for the lower levels as well (“Obama, a man”). This is a type of deductive reasoning, but it is actually more reminiscent of Te than Ti! How can that be? The reason is that here we see some top-down logic that actually leaves some theoretical nuances on the table. We reason in an efficient manner, and we don’t care about the possible exceptions to the rule. “What possible exceptions could there be,” you ask?
Well, for example, both the Buddha and the philosopher Immanuel Kant reasoned that mortality and immortality could never be proven. There were so-called “un-decidable” categories. For example, if a person is immortal, we will never see his immortality; we will merely see that he keeps living on, no matter what happens. But living past one’s last bout with fate does not guarantee that one won’t die the next time around (and if you thought that, that was because you used induction to try and establish the truth of the matter).
Likewise, with mortality, you don’t see the termination of consciousness. You only see consciousness leaving the body. So does consciousness terminate, or does it “live on” outside of the body? According to Kant and the Buddha, we cannot prove anything, either one way or the other.
These examples from Kant and the Buddha are reminiscent of the types of questions that are at the forefront of consciousness to a person that uses Ti with N (not necessarily in that order). In a similar situation, a Te user – even as he is using deductive reasoning – would be far more likely to simply look to the external facts and disregard these considerations by Kant and the Buddha as sophistries that are not relevant in the real world.
So in our final example, we actually provide an instance of a deductive argument that sits better with Te than Ti. But we also see that even when Te is prone to deductive reasoning, its lifeblood is still the facts, first and foremost. As we have said in this article, we do not deny that one can make an argument for Te being reminiscent of deductive reasoning, but based on the arguments that we have laid out above, we do contest that Te – with its preoccupation with efficiency and facts – could be said to be as deductively oriented as Ti.