1. Te – extroverted Thinking
Te is the primary way TeSi’s interact with the world around them. Te is all about effectiveness and getting things done. It is the TeSi’s primary decision-making process, which means that if a decision is needed in the moment, they will rely on what makes the most sense logically. They are primarily concerned with moving forward and are not interested in wasting time and energy nitpicking a solution to death before applying it. They make the best decision they can given the probabilities they’re presented with. The most effective functional or workable solution is often obvious to them, and they are masters of maximization. Te can also make them quite competitive.

2. Si – introverted Sensing
TeSi’s naturally use Si to catalogue experiences and information they deem important. In particular, they remember their impressions of experiences they’ve had. They have an organized internal world and their mind can easily put similar pieces of information into appropriate categories. They learn straightforward, practical systems, rules, and strategies with ease and grace. Si gives the sense of the TeSi being grounded and can make them seem like they have a very linear, black and white way of thinking about things. (Though in reality they may see everything as shades of grey.)

3. Ne – extroverted iNtuition
Ne is the part of the TeSi that craves new experiences and ideas. For example, when coming up with an idea to execute a project, they can take a lot of details they’ve gathered from previous experience and put them together to form a really great concept. Ne can also fuel sudden “lightbulb” moments where an idea strikes them out of nowhere as they’re talking. It makes the TeSi likely to enjoy taking disparate things and thoughts and gluing them together to see what happens. It can also cause them to lapse into a sort of factual story-telling mode at any moment.

4. Fi – introverted Feeling
Fi is their last function. Fi helps them to assess situations to see how things match up to their values and beliefs. They may think of their Fi as their “gut instinct”. It helps them learn to be sensitive to the values and feelings of those around them. It can act as a warning system when they think a decision makes sense logically, but somewhere inside, Fi is the alarm saying it’s a bad idea. However, because Fi is the TeSi’s weakest function, they will often act with the swift decisiveness of Te first, before considering how their actions might affect the feelings of others or taking time to think about whether their decision lines up with their values. As the TeSi ages, they get much better at using their Fi towards the beginning of their decision-making process. Although the most effective option takes priority, they become more aware and careful about doing things that would hurt those around them.