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Comment by simonw | Hacker News Reader

Because I collect definitions of "agent", here's the one this book uses:

> An agent is something that acts in an environment; it does something. Agents include worms, dogs, thermostats, airplanes, robots, humans, companies, and countries.

https://artint.info/3e/html/ArtInt3e.Ch1.S1.html

I think of this as the "academic" definition, or sometimes the "thermostat" definition (though maybe I should call it the "worms and dogs" definition).

Another common variant of it is from Peter Norvig and Stuart Russell's classic AI text book "Artificial Intelligence: A Modern Approach": http://aima.cs.berkeley.edu/4th-ed/pdfs/newchap02.pdf

> Anything that can be viewed as perceiving its environment through sensors and acting upon that environment through actuators

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It always amazed me that different branches of CS, AI/ML and Complex Systems/Complexity Sciences have different views on agents.

Objects in OOP - something which can have properties/attributes, and methods (verbs/commands). Usually modeled after a real-life/domain enitites.

Aggregates in Domain-Driven Design (DDD) - transactional clusters of objects modeling a collections of entities in the domain.

Actors in Actor Model / Active Objects - a something we can sen messages to, and receive messages from, and which may have some business logic.

Agent-Based Modeling and Simulations (ABM) defines agents as a proxy for a decision maker.

Digital Twins - a more realistic proxy/replica for a real life person, object, or process.

Multi-Agent Systems (MAS) in how to use asgents to solve or optimize a real problem in production.

RL/MARL (Muti-Agent Reinforcement Learning) on how to train an ML algorithm without supervision (i.e. a labeled dataset), by placing agents in an environment capable to automatically provide rewards/punishment feedback.

LLM Agents - dynamically generated intelligent business process workflows (including Robotic Process Automation - RPA aka Tool Use/Function Call).

Also:

Smart Contracts - agents with an attached cryptocurrency wallet/account/address, capable to receive and make payments autonomously.

How's about: LLM Agent: any packaging of the use of AI such that the details of using said AI are packaged, hidden, and the user of this LLM Agent does not need to concern themselves with AI at all, only the intelligence services provided by what is now a simulated personality the user can willfully self deceive they are working with a human.

aka "delegation", "ousourcing", "serverless", and "not my busienss, do it ASAP, I don't care how" ;)

Exactly, you know AI Agents will ultimately be "just make it work, I don't care how", so why don't we just stop the game and make that?

Try replacing "AI Agentic Workflow" with "just make it work, I don't care how" in your startup's pitchdeck, and tell us how many VCs replied back ;)

The funny part is these both say the same thing to the customer.

FWIW I had a professor that defined "robotics" in the same way (we even had a quite philosophical debate on whether automatic doors are robots). I ended up liking Norvig and Russell's definition better by appending the word "autonomously".

Another interesting word that is quite out fashion nowadays is "cybernetics": "Cybernetics is the transdisciplinary study of circular causal processes such as feedback and recursion, where the effects of a system's actions (its outputs) return as inputs to that system, influencing subsequent action." [1]

Having studied Control Engineering in college, to me, all these things are feedback control loops. [2]

[1] https://en.wikipedia.org/wiki/Cybernetics [2] https://en.m.wikipedia.org/wiki/Feedback

I was literally compiling a list of "agent" synonyms at lunch today. My favorite and most accurate so far is "doer".

Agent - time-like, energy-like (you need a GPU to compute it). An agent changes the shape of the environment it operates in, including its own shape. You can count agents, their volume of operations, their speed of changing shapes (volumetric speed), acceleration… The Big Bang had zero intelligence (with maximal potential intelligence) but was and still is maximally agentic.

Same way we have many definitions of life (virus is alive or not? It’s very agentic, COVID killed millions but the shape, intelligence is small. Same with computer viruses), we have many definitions of agency, better to use the broadest and most physical one.

Intelligence - space-like, matter-like (LLM is a bunch of vectors, a static geometric shape, you just need memory to store it). It’s a static geometric shape. It can have analogs of volume, mass and density. The static 4D spacetime of the universe or multiverse is maximally intelligent but non-agentic.

Add this please ->https://jdsemrau.substack.com/about

To save a click: "We define cognitive autonomous agents as an entity designed to perform tasks autonomously by combining four key components: goals, reasoning/planning, memory, and tools."

Thank you!

So basically an agent is a procedure, by this definition: it takes parameters (environment) and acts upon that by executing side effects. An email filter is an agent. A database trigger is an agent.

> it takes parameters (environment)

I think it's better to imagine agent as something that physically placed inside the Environment, and actually modifying/changing/mutating it in place.

> An email filter is an agent. A database trigger is an agent.

you're missing the "I" (Intelligence) part - the filtering logic in the email filter, or a business logic in the DB trigger/stored procedure/CGI script/AWS Lambda function/etc.

But yes, an agent doesn't have to be Intelligent, it can be a Dumb Agent / NPC / Zero-Intelligence Trader.

Can you explain the "intelligence" part? Can't one derive a decision tree of any "intelligent agent" that is in essence no different than a classically programmed algorithm?

Yes, for Computational Agents you will either code "Agent Intelligence"/"Agent Cognition" algorithmically, or using AI/ML/LLM (either by pre-training, or using continous re-training for Adaptive Agents).

Useful abstaractions:

  - FSM/State Machines
  - Behavior Trees
  - Behavior Action Trees
  - Workflow Orchestration
  - Dataflow (mostly for pipelines transforming LLM Prompt into LLM Reponse)

Another option is to outsource it to a Human, like it was in the ALICE program[1], e.g. Human-in-the-Loop, Participatory Simulation, RLHF, Whole-brain computer simulation, like in The Age of Em[2] (SciFi).

See:

https://news.ycombinator.com/item?id=43409240

---

1. https://www.media.mit.edu/projects/participatory-simulations...

https://ccl.northwestern.edu/papers/partsims/cscl/

2. https://ageofem.com/

Just replying here to tell you I replied to a question (cisco) you asked me in case you miss it. Thanks!

The problem I see with this definition is that we have things called RAG agents which don't technically act in any environment except for provide information.

Is that a problem with the definition of agents, or a problem with sticking the word "agent" on something that doesn't meet the definition of an agent?

Is that not a summary and translation agent? For some reason only the user knows, they do not want to or cannot read the entire RAG source, so they use their summary and translation agent to give them summaries and to translate the technical jargon they do not understand. That Agent becomes a teacher of the RAG source. I see no problem with the Agent definition when given this perspective.

How are agents different from daemons? And are both essentially cybernetic feedback loops?

(1) Daemons run usually in the background while agents are main loop.

(2) Daemons are predefined and can't adapt to changes easily -- this is a function of narrow AI vs general AI (not to be confused with AGI)

(3) Daemons have few interactions with the environment while for the agent the environment (tools, sensors, plans, memory, and context) is everything.

These are just a few from the top of my head.

written 2023 , pre-LLM hype

LLM hype was firmly with us with the coming of ChatGPT, November 2022. Records in signing up aren't for nothing.

I don't think so. I own the printed version and it starts discussing GPT in page 6 already.

agent has almost as many definitions as set.

I would say the situation for "agent" is about 10,000 times worse than it is for "set," since all the definitions for set are essentially different ways to make Frege / Cantor more rigorous. The underlying scientific concept hasn't actually changed that much: "belonging to a set and a few certain operations are primitives, join these primitives with formal logic." This is the idea behind a famous intro book, Paul Halmos's Naive Set Theory. Even a set theory with Russell's paradox is scientifically defensible, it just needs refinement.

In contrast, "agent" discusses a huge range of scientific concepts, and I have yet to see a single definition of agent that holds up to scientific scrutiny. This book has managed to define "agent" in a way that is entirely equivalent to "physical object" - putting worms and thermostats in the same category broadens the category to utter uselessness. By this definition, Jupiter is an agent.

The only utility of definitions like this is for dishonest people to cheat at arguments: claiming simple tools are agents, then arguing they are like dogs and humans, which are also agents. It's a total waste of time, coming from AI's shameless disrespect for scientific standards.

> By this definition, Jupiter is an agent.

Is it? What task was it designed to carry out autonomously? Where are the inputs and the logic hiding?

> for dishonest people to cheat at arguments

Only if the goal is to deceive. If the communication is well intentioned then there is nothing inherently wrong with it despite it not being to your liking.

The problem is they also put "worms" in the same category, and they aren't designed by humans to do anything! Why is it that the natural laws of a worm responding to Earth's environment are distinct from the natural laws of Jupiter responding to the solar system's environment? I suppose because of complexity. But then why is a thermostat different from Jupiter despite being considerably simpler? I suppose because it was designed by humans and can be controlled. But then what about the worm, which is just as natural as Jupiter? "Thermostat" is especially problematic because a cheap thermostat is very simple to describe completely as a thermo-electric balance equation: it is certainly simpler to describe than an irregular ball rolling down an irregular hill. Yet apparently the thermostat is an agent and the ball is not.

The definition is just incoherent! "Sometimes an agent is deterministic and in this case the term only includes manmade tools, other times an agent is an apparently nondeterministic automaton and in this case we can include natural life." It only allows "agent" to be labelled ad hoc, and in particular blurs the distinction between "nondeterministic tool" and "lifeform" in ways that are scientifically unjustifiable. The only people this pointless word game benefits are liars like Sam Altman and Mustafa Suleyman; if people are well-intentioned then these definitions bring nothing but confusion.

By your own logic you could argue that humans are just as natural as worms (and Jupiter). I don't know if you'd then extend that to include anything we build as well but even if you don't there's already a glaring issue - your criteria has resulted in the terminology being rather useless. It appears to include approximately everything or approximately nothing.

Similar logic can be used to argue that machines are no different from rocks.

At the end of the day it's an argument of semantics so it's always going to come down to some fairly arbitrary criteria. You could survey people to determine common usage. You could establish a standards body to define it. Probably some other options as well.

Recall that Pluto used to be considered a planet.

I think their apparent definition seems fairly reasonable, although it's far from the only one. It appears to amount to living organisms plus any machinations constructed by said organisms that respond to the environment in some clear manner. Thus worms, dogs, humans, and thermostats. Probably not bicycles or hammers. Drones probably only qualify when operating in an autonomous mode. I'm not seeing the issue.

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