Stable Diffusion can run on Intel CPUs through OpenVINO if you don't have a GPU or the funds to rent one online (Google Collab is often used). You still need a decent amount of RAM (running SD takes about 8GB, training seems to run at 6-8GB) so I'd consider 12 or 16GiB of RAM to be a requirement.

There's a huge difference in performance (generating an image takes 10 minutes rather than 10 seconds and training a model would take forever) but with some Python knowledge and a lot of patience it can be done.

Apple's Intel Macbooks are infamous for their insufficient cooling design for the CPUs they chose, which won't help maintaining a high clock speed for extended durations of time; you may want to find a way to help cool the laptop down to give the chip a chance to boost more, and to prevent prolonged high temperatures from wearing down the hardware quicker.

I’m on Windows, sorry. There are some colabs where you can do both the training and generation though.

theres lots of online services too if you dont have the hardware - e.g. https://www.astria.ai/