[the8thbit]

"There's a pretty clear difference between the 'finetuning' offered via API by GPT4 and the ability to do whatever sort of finetuning you want and get the weights at the end that you can do with open weights models."

Yes, the difference is that one is provided over a remote API, and the provider of the API can restrict how you interact with it, while the other is performed directly by the user. One is a SaaS solution, the other is a compiled solution, and neither are open source.

""Brute forcing" is not the correct language to use for describing fine-tuning. It is not as if you are trying weights randomly and seeing which ones work on your dataset - you are following a gradient."

Whatever you want to call it, this doesn't sound like modifying functionality in source code. When I modify source code, I might make a change, check what that does, change the same functionality again, check the new change, etc... up to maybe a couple dozen times. What I don't do is have a very simple routine make very small modifications to all of the system's functionality, then check the result of that small change across the broad spectrum of functionality, and repeat millions of times.

[Kubuxu]

The gap between fine-tuning API and weights-available is much more significant than you give it credit for.

You can take the weights and train LoRAs (which is close to fine-tuning), but you can also build custom adapters on top (classification heads). You can mix models from different fine-tunes or perform model surgery (adding additional layers, attention heads, MoE).

You can perform model decomposition and amplify some of its characteristics. You can also train multi-modal adapters for the model. Prompt tuning requires weights as well.

I would even say that having the model is more potent in the hands of individual users than having the dataset.

[thayne]

That still doesn't make it open source.

There is a massive difference between a compiled binary that you are allowed to do anything you want with, including modifying it, building something else on top or even pulling parts of it out and using in something else, and a SaaS offering where you can't modify the software at all. But that doesn't make the compiled binary open source.

[emporas]

> When I modify source code, I might make a change, check what that does, change the same functionality again, check the new change, etc... up to maybe a couple dozen times.

You can modify individual neurons if you are so inclined. That's what Anthropic have done with the Claude family of models [1]. You cannot do that using any closed model. So "Open Weights" looks very much like "Open Source".

Techniques for introspection of weights are very primitive, but i do think new techniques will be developed, or even new architectures which will make it much easier.

[1] https://www.anthropic.com/news/mapping-mind-language-model

[the8thbit]

"You can modify individual neurons if you are so inclined."

You can also modify a binary, but that doesn't mean that binaries are open source.

"That's what Anthropic have done with the Claude family of models [1]. ... Techniques for introspection of weights are very primitive, but i do think new techniques will be developed"

Yeah, I don't think what we have now is robust enough interpretability to be capable of generating something comparable to "source code", but I would like to see us get there at some point. It might sound crazy, but a few years ago the degree of interpretability we have today (thanks in no small part to Anthropic's work) would have sounded crazy.

I think getting to open sourcable models is probably pretty important for producing models that actually do what we want them to do, and as these models become more powerful and integrated into our lives and production processes the inability to make them do what we actually want them to do may become increasingly dangerous. Muddling the meaning of open source today to market your product, then, can have troubling downstream effects as focus in the open source community may be taken away from interpretability and on distributing and tuning public weights.