There are four major technological approaches to augmenting the mind: Capacity, Capability, Relocation, and Longevity. While interest in these approaches has been with us for decades, only recent technology has made them plausible. Of course, these approaches are more than just what their labels indicate and none are mutually exclusive.

Capacity means expanding the mind's storage. This is more than adding memory, since this memory must be comparably accessible. The enhancements to Capability are only limited by imagination. Many proponents of this approach believe a quantitative change in brain capability will result in a qualitative change. Relocation proposes to upload the brain (or mind or consciousness) to a computer. More than just relocating the brain, this is also copying and more than one copy is possible. Extending the Longevity of the mind is incidental to the extension of life, but is the primary goal of uploading and digital immortality.

Current examples of increasing Capacity include products such as Microsoft's MyLifeBits™ and DARPA's Lifelog. Projects enhancing brain Capability range from genetic engineering and the super-intelligences of AI (BM2), to the extremes of smart drugs and super-brain computers (Jupiter Brains, etc.). Sometimes referred to as Whole-Brain Emulation, the most significant current effort aimed at Relocating the brain is the Blue Brain project using IBM's Blue Gene computer. Examples of Longevity range from extending life (cryonics, Life Extension) to extending aspects of mind (digital immortality) to extending brain existence (uploading).

All these approaches have historical precursors and there are many fictional examples in popular culture, especially science fiction. Embedding memory chips in the brain and connecting the brain to computer memory are but two examples of earlier speculation on increasing Capacity. Initial attempts at enhancing Capability through artificial intelligence resulted in a division into weak and strong AI, and the extrapolation from strong AI to Transhumanism. Relocating brains has long been a staple of science fiction: first to robots, then computers, androids, and now clones. Before we sought digital immortality for Longevity there was analog immortality, and its prime example is Leonardo da Vinci. While it's estimated that only a fourth of Leonardo's Notebooks survive, those may still prove to be more enduring than our obsolescing digital media.

The major thrust of the paper, however, is not simply to describe the primary technological approaches to augmenting the mind, but to evaluate their practicality: e.g., their progress to date, how much more work is needed, and the likelihood of success. Finally, the paper will consider the potential of each for the good or ill of humanity, i.e., the ethical, legal, and social implications.