Your ego has set itself the task of self-preservation
The other agency of the mind, which we appear to know the best and in which we recognize ourselves the most easily—what is known as the ego—was developed out of the cortical layer of the id (ed. the part of the mind in which innate instinctive impulses and primary processes are manifest), which, being adapted for the reception and exclusion of stimuli, is in direct contact with the external world.
Starting from conscious perception, it has brought under its influence ever larger regions and ever deeper layers of the id; and, in the persistence with which it maintains its dependence upon the external world, it bears the indelible stamp of its origin (as it might be "Made in Germany"). Its psychological function consists in raising the processes in the id to a higher dynamic level (perhaps by transforming freely mobile into bound energy, such as corresponds to the preconscious condition); its constructive function consists in interposing, between the demand made by an instinct and the action that satisfies it, an intellective activity which, after considering the present state of things and weighing up earlier experiences, endeavors by means of experimental actions to calculate the consequences of the proposed line of conduct. In this way the ego comes to a decision whether the attempt to obtain satisfaction is to be carried out or postponed or whether it may not be necessary for the demand of the instinct to be altogether suppressed as being dangerous. (Here we have the reality principle.)
Just as the id is directed exclusively to obtaining pleasure, so the ego is governed by considerations of safety.
The ego has set itself the task of self-preservation, which the id appears to neglect It makes use of sensations of anxiety as a signal to give a warning of dangers threatening its integrity. Since memory-traces can become conscious just as much as perceptions, especially through their association with verbal residues, the possibility arises of a confusion which would lead to a mistaking of reality. The ego guards itself by establishing a function for reality-testing, which can be allowed to fall into abeyance in dreams on account of the conditions governing the state of sleep. In its efforts to preserve itself in an environment of overwhelming mechanical forces, the ego is threatened by dangers that come in the first instance from external reality, but not from there alone. Its own id is a source of similar dangers and that for two different reasons. In the first place, an excessive strength of instinct can damage the ego in the same way as an excessive "stimulus" from the external world. It is true that such an excess cannot destroy it; but it can destroy its characteristic dynamic organization, it can turn the ego back into a portion of the id. In the second place, experience may have taught the ego that the satisfaction of some instinctual demand that is not in itself unbearable would involve dangers in the external world, so that an instinctual demand of that kind itself becomes a danger. Thus the ego is fighting on two fronts: it has to defend its existence both against an external world that threatens it with annihilation and against an internal world that makes excessive demands. It adopts the same methods of protection against both, but its defense against the internal foe is particularly inadequate. As a result of having been originally identical with this enemy and of having since lived with it upon the most intimate terms, the ego has the greatest difficulty in escaping from the internal dangers. They persist as threats, even if they can be temporarily held in check.
Yet, certainly, the wise learn many things from their enemies; for caution preserves all things. From a friend you could not learn this, but your foe immediately obliges you to learn it. For example, the states have learned from enemies, and not from friends, to build lofty walls, and to possess ships of war. And this lesson preserves children, house, and possessions.
The present theory then must be considered to be a suggested program or framework for future research and must stand ...
It’s saying no.
That’s your first hint that something’s alive. It says no. That’s how you know a baby is starting to turn into a person. They run around saying no all day, throwing their aliveness at everything to see what it’ll stick to. You can’t say no if you don’t have desires and opinions and wants of your own. You wouldn’t even want to.
No is the heart of thinking.