Neither the bare hand nor the unaided intellect has much power; the work is done by tools and assistance, and the intellect needs them as much as the hand. As the hand's tools either prompt or guide its motions, so the mind's tools either prompt or warn the intellect.

The tools of the mind that Bacon refers to here are those of the "machine for thinking" that he sets out in The New Organon. As the mind tends to wander and miss the point when left unguided, the various steps of Bacon's scientific method lead it through the process of investigation. The tools of induction prompt the mind into investigating carefully, and warn it against moving immediately to general axioms. Bacon argues that his mental tools can be used by anyone with a little intelligence; by prompting and warning, they take individual error out of natural philosophy.