1. Our physical defense against outer attacks. This backfires, for it affirms that the attacks are real and that we can be injured (see W-pI.153.1-5). Further, the idea of self-defense is simply an excuse to attack and so leads to guilt (see attack). 2. Closely related to this outer defense is the ego's system of psychological defense (the primary one being projection), which also backfires, for it too affirms that what it defends against—internal guilt—is real. 3. The ego's true purpose behind these defenses is to do precisely what they do: reinforce the reality of outer attack and inner guilt. Reinforcing our fear and guilt is how the ego defends its "reality" and so defends itself against God. 4. Yet to keep our allegiance—to defend itself from being relinquished—it must also offer us "gifts." Its chief defense in this sense (its most boasted gift) is the special relationship (see T-17.IV.5). 5. The Atonement is a defense, which does not attack and does not make real what it defends against (see T-2.II.4). For it protects us from illusions by showing us their unreality. See denial.