The GPT-4 base model (gpt-4-base on the API) is the inframodel of GPT-4, trained with pure self-supervised learning. So far, only a small number of researchers outside OpenAI have been granted access to it.

quotes about the GPT-4 base model

talking to the base model can induce madness

β€” roon, Twitter post

it is much scarier than code davinci for reasons I can’t really explain. perhaps the latent feeling that it’s smarter than me and mostly toying with me

we haven’t begun to plumb the depths of its intelligence

β€” roon, Twitter thread