Do Heat Seeking Missiles Have Teleology?

(S. Joshua Swamidass) #21

Circling back here, I’m curious how @dga471 would summarize lessons from the other thread on determinism and teleology.


I think I have a different understanding of what teleology is. Using the heat seeking missile example, a teleological explanation for the whole missile is that it is meant to shoot down airplanes as part of a military operation. The fuel in the missile is there to hurl the missile towards a plane. The sensor in the front portion of the missile is meant to track the heat given off from an airplane’s exhaust. Teleology is defined as “the explanation of phenomena by the purpose they serve rather than by postulated causes”. I’m not clear on how this definition is being used with reference to life.

(Daniel Ang) #23

This is my summary of the discussion:

From the other thread, while initially @PdotdQ pointed out that no theory of physics (even classical physics) gives complete predictability, we still agreed that classical physics gives a fundamentally deterministic picture of the world, while quantum theory (and anything that is touched by it - including quantum field theory and quantum gravity) gives a fundamentally indeterminate picture of the world, unless if one assumes non-locality or superdeterminism.

Nevertheless, the more important point is that @EricMH’s definition of intrinsic teleology seems to flawed regardless of which theory of physics you choose.

If you assume classical physics, then most things are deterministic, so everything is teleological, including heat seeking missiles. As everything is teleological, it seems to cease to be a meaningful term.

If you assume quantum physics, then nothing is deterministic, so nothing is teleological, including heat-seeking missiles.

(Catholic Astrophysics Postdoc) #24

While I disagree with this:

I agree with Daniel’s conclusion:

I would also add that I think in theories with predictability problems (i.e. anything with special relativity, as well as general relativity except for some specific spacetimes), it might be difficult (or even impossible) to compute Eric’s P(X)'s in practice.

(S. Joshua Swamidass) #25

So, to summarize, it seems that this is @EricMH’s definition of teleology.

Looks like @nwrickert is right.

@EricMH is claiming that if something will certainly happen, then it is purposed. Applying this definition, missile is going to hit its target with 100% certainty. So by this definition a missile is not intrinsically purposed until it is inevitably going to its target.

Anything inevitable, for example physical death, is therefore teleological. It seems that he is equivocating determinism with teleology.

(Eric Michael Holloway) #26

I’m saying that if an entity is determined by the future, i.e. converges, then it is intrinsically teleological. Physics says timelines should diverge, so the opposite occurrence indicates something other than the laws of physics at work.

A further qualification I’d add is this must be a net convergence. In other words, there cannot be local convergence that is offset by divergence elsewhere.

To continue beating the mutual information horse, an intrinsically teleological entity would cause a net increase of mutual information to come about, since H(X[n]|X[n+1]) = 0 and H(X[n]|X[n-1]) > 0, so I(X[n];X[n+1]) > I(X[n];X[n-1]).

(S. Joshua Swamidass) #27

@dga471 and @PdotdQ, is this correct?

Mutation information between what and what?

I don’t understand how this applies at all. Life is not a closed system. There is no evidence that any order we find in life is not offset by disorder elsewhere.

(Eric Michael Holloway) #28

Second law of thermodynamics.

(Daniel Ang) #29

This language of “convergence” is confusing and unclear to me.
(I’ve never encountered this term in physics.) But based on your clarification that you are referring to the 2nd law of thermodynamics, what you seem to really saying here is simply that a system is teleological if it violates the 2nd law of thermodynamics. Am I getting you right? And your reference to “local convergence” and “net convergence” is saying that this violation happens even if the system is isolated.
(Edited for clarity)

(S. Joshua Swamidass) #30

That seems to be a much clearer statement.

However, a heat seeking missile does not violate the 2nd law of thermodynamics. In fact, it would most likely pushing things in the direction of the 2nd law, by increasing entropy. I’m not at all clear how to make this coherent.

(S. Joshua Swamidass) #31

@EricMH, thank you for engaging us. We are making a good faith effort here, but your position does not make much sense to us. Can you help us out?

(Catholic Astrophysics Postdoc) #32

Yes if you assume the many-worlds interpretation of quantum mechanics. The 2nd law of thermodynamics has nothing to do with timelines diverging.

Barring issues of whether one can actually test his teleology in practice, here are my issues with @EricMH’s definition of intrinsic teleology, P(X[n]|X[n-1) < 1 and P(X[n]|X[n+1) = 1.

  1. The second part, P(X[n]|X[n+1) = 1 seems clear to me. This is the statement that the future dictates the behaviour of the object (what @EricMH calls converging behaviour). To me, this condition is placed to capture a sense of purpose for the object. My problem with this part is that it seems to point more towards “inevitability” than “purpose”. As @swamidass and @nwrickert points out, inevitability does not equal purpose.

  2. The first part, P(X[n]|X[n-1) < 1 is the statement that the behaviour of the object is not fully prescribed by its past. This is confusing to me. It seems to me that in light of quantum mechanics (barring nonstandard physics like nonlocality and superdeterminism), every object already satisfies this criterion (as we discussed in the other thread with @dga471).

(Edward Robinson) #33

I don’t dispute the claim that a heat-seeking missile exhibits teleology, but regarding the above formulation, I want to remind everyone that in the Aristotelian language which underlies the notion of teleology, telos (aim or end) is not something other than a cause, but a kind of cause. So the formulation “by the purpose they serve rather than by postulated causes” is inherently inaccurate. The division between “purpose” and “cause” in that sense is modern. At the very least, the sentence would need to be modified to: “by the purpose they serve rather than by postulated efficient causes”; this would not prejudge the central question about teleology, i.e, whether the telos (end toward which something aims) counts as one of the true causes of its behavior.

(Edward Robinson) #34

As someone who is like yourself sympathetic with design language, I’m puzzled by this remark. See my clarification of terminology in my reply to T. aquaticus. By “prior causes” do you mean “efficient causes”? But why do “efficient causes” rule out “final causes” (which is what “teleology” pertains to)?

Are you arguing that life is teleological, but that guided missiles aren’t? I don’t think most ID people would agree with you. Indeed, much of ID discussion involves parallels between machines devised by man, and living organisms. Dembski himself has distinguished between “external teleology” (such as is imposed by the watchmaker when he makes a watch) and “intrinsic teleology” (such as is found in organisms). Both are examples of teleology. You seem to be undercutting much of ID thought by denying the notion of teleology to clearly end-driven man-made contrivances.

If you mean that the missile has no consciousness of what it is doing or why it is flying on the path it flies on, then of course I agree with you. But consciousness it not a requirement for teleology. That’s obvious not only from machines, but even from, say, plants. Would we say that plants are “conscious”? We might say they have a crude organic striving, but not that they are thinking about what they are doing; they have no nervous system, no brain, etc. End-directed behavior doesn’t require consciousness within the striving entity. It does, however, require consciousness somewhere – if not within the organism (as in the case of animals) then outside the organism (as in the cases of guided missiles or clocks).

The guided missile is to me a very good example of teleological behavior – of what Dembski calls an “external” kind. The teleology is given to the missile by its designer. If a guided missile isn’t teleological, I don’t know what human construction would be.


I politely disagree. By putting “effeciency” into the definition you are biasing the definition. In order to determine effeciency we need to assume a purpose which is teleology. Effeciency is how well something attains a goal, and that is inherently teleological.

(Eric Michael Holloway) #36

There is intrinsic and extrinsic teleology. Extrinsic is the heat seeking missile, where its present is a product of the past, but is engineered to match a target. Intrinsic is where the present is a product of the future, which could violate the 2nd law of thermodynamics, because intrinsic teleology could move from high probability states to low probability states.

ID focuses on extrinsic teleology. My position is idiosyncratic in that I claim intrinsic teleology is necessary for extrinsic teleology.

To tie into mutual information: extrinsic is an instance of mutual information, intrinsic is the creation of the mutual information.

(Steve Schaffner) #37

My conclusion from having read this thread is that I understand not a single thing that’s being said here. I don’t understand why the existence of mutual information says anything about teleology, I have no idea what it means for physics to say that timelines should diverge (timelines of what? in what space? what part of physics is this?), the apparent equation of determinism with teleology leaves me simply flummoxed. If anyone ever ends up understanding what the argument is, I’d really appreciate a summary.

(Edward Robinson) #38

I see from your response that you do not recognize the way I am using the term “efficient cause”. You are using the term “efficient” in the modern sense of an efficient machine, or efficient management, or the like. I thought I indicated that I was using Aristotelian vocabulary. In Aristotle’s scheme of causality there are four causes, all equally “causes”: material, efficient, formal, and final. The final cause, or end, is in Greek the telos. It is from telos, end or aim or goal, that we derive the term “teleological” that Eric is using. Since Eric is using a Greek conception to discuss causality, I was trying to fill out the scheme in consistent Greek language.

I was not picking on you in particular, since Eric made the same terminological error (error in Aristotelian terms, that is), and I pointed it out to him.

The efficient cause for Aristotle is the “doer” of the action in our typical everyday sense; e.g., the efficient cause of the flight of a football is the kicker, or his kicking action. The modern scientist, in speaking of causes, is typically concerned only with what Aristotle calls the efficient cause, i.e., what thing or force pushed, pulled, propelled, attracted, etc. another? So science postulates movements of continental plates at the cause of earthquakes, or electric current in a wire as the cause of its magnetic field, or a hydrogen ion as the cause of acidity, or whatever. But for Aristotle, efficient causes, though real and necessary in explanation, provide only an incomplete explanation. A full explanation makes use of the other causes all well.

You can look up “the four causes” in any number of places, but Mortimer Adler’s Aristotle for Everybody gives a pretty good layman’s summary.

The definition of “cause” implied in your quoted sentence presupposed the modern scientific understanding of cause and ruled out the Aristotelian understanding of cause, because it opposed “cause” to “purpose”, when for Aristotle a “purpose” (in the sense of end, aim, goal of striving) is just as much as cause as the kicker’s foot action is the cause of the movement of the football.

Since Eric is insisting on using the language of teleology, he needs to insist on the genuine explanatory (and hence causal) meaning of telos or end, and therefore he must not accept the dictionary (?) definition you gave which relegates purpose to a realm outside the realm of causes.

Basically, your refutation of Eric is based on causality as conceived of by Descartes, Bacon, Hume, etc., whereas Eric’s language presupposes causality as conceived of by Aristotle, Aquinas, etc. You are talking two different philosophical languages, as if Eric spoke in English and you replied in Russian. But the problem was compounded when Eric made the same linguistic shift that you did, implicitly treating the end or aim of the guided missile as if it wasn’t a genuine cause of the missile’s flight. He unwittingly wavered between ancient and modern languages. That’s why I replied to him as well as to you.


I’ve read through this and I still have no idea what you mean by teleology.

(Edward Robinson) #40

Technically, “teleology” means “the study or science of ends/purposes.” But quite often the idea of “the study or science of” is left out, and when we say that a process is “teleological”, we mean that it is end-driven, led by a goal or purpose, “striving” as it were to attain that goal or purpose or end.

The thing toward which the striving is directed is called its “final cause” or telos.

The classic example is the acorn and the oak tree.

In Aristotle’s language, the oak tree is both the efficient cause of the acorn (since oak trees generate acorns) and also the final cause of the acorn (since the end or goal of the acorn is to make another oak tree).

If you want to focus on the process rather than the static entities, you can say that the process by which the acorn becomes the oak tree is teleological, i.e., as the acorn matures it continues to drive toward becoming an adult oak tree, until it achieves that end. Thus, the oak tree is the “final cause” or “telos” of the acorn’s maturing process.

Note that this does not rule out considering the process in terms of “efficient cause” (to use Aristotelian language, in which “efficient” has nothing to do with “efficiency” as we commonly use the term); the “efficient cause” of the acorn’s maturation process would be the taking up of water and nutrients from the soil, and the various internal mechanisms by which the acorn turns those things into a growing body of an oak.

For Aristotle, both “efficient cause explanation” and “final cause explanation” (i.e., teleological explanation) are necessary to understand why an acorn turns into an oak. Aristotle thus uses “why” in a fuller sense than that typically used in modern scientific explanation (where “why” is often really just “how”).

The point is that for Aristotle, teleological causation is real, not merely a verbal gimmick imposed on reality by misleading language. It actually helps to explain aspects of what happens in nature.

Does that now make sense to you? Do you now understand how I’m using the terminology?

If you do, then you will understand what I said earlier. I agreed with you against Eric that the heat-seeking missile’s flight was “teleological”. The missile is guided by an end; it is “trying” (so to speak) or “striving” to knock that engine-bearing airplane out of the sky. It was designed to do so. Its teleology was built into it by the engineers who designed it. It’s perfectly appropriate to explain its actions in terms of its purpose. One could also explain its actions in terms of efficient causes only, e.g., thrust, the chemical energy released when the fuel burns, the various devices used to make it change direction and the mechanical laws of their working, etc. But for Aristotle, such efficient-cause explanation, while totally valid, would be missing something; it would be missing the purposive behavior of the missile, its teleological intent.

Eric made out that the teleological behavior of the missile was somehow illusory or not real, because its motion could be explained by “prior” causes (by which he seemed to mean efficient causes). But that reasoning betrays the whole way of thinking of Aristotle, because it denies the metaphysical reality of final causes. They are just as real as efficient causes, for Aristotle (and the tradition following him, e.g., the Scholastics).

The behavior of the missile is every bit as teleological as the behavior of the acorn growing into the oak tree. The difference is that the teleology or end-drivenness in the case of the missile is imposed from outside, upon pieces of matter such as metal, wires, tanks of fuel, etc., by the design of human engineers, whereas the teleology of the acorn is internal or intrinsic, i.e., the acorn contains its own natural principle of end-drivenness – as do all living things.

Of course, the missile is not conscious, in the normal sense of the word, but then, neither is the acorn, so conscious striving for ends isn’t required for an activity to be teleological, in either the inorganic or organic realm.

Eric was correct to say that in a sense, efficient causes (though he didn’t use the term) proceed from the past, whereas final causes proceed from the future. In that sense, efficient cause explanation is focused on the past (what previous pushes, pulls, collisions, attractions, repulsions, etc. caused this to happen?), whereas teleological explanation is focused on the future (where is this process or thing headed?). But he confused matters by implying that future-drivenness and past-drivenness can’t truly exist in the same process – which for Aristotle, they can. Both efficient causes and final causes can operate at one and the same time, in Aristotle’s analysis.

I hope this helps, because it’s all I have time for. But the Adler book (written by a famous Chicago professor of Greek philosophy, who was also one of the leading proponents of Great Books education in America) is a good popular introduction to Aristotle. It has references at the back to the relevant Aristotle passages for the reader who wants to go beyond the popular summary. I recommend it for those who want to get their feet wet in Aristotelian thought without getting buried in decades of academic discussion and commentary.