The Ten Factors of life can he found in the Lotus Sutra in Chapter 2, Expedients. The passage that contains the Ten Factors is recited as part of the daily practice of Nichiren Buddhism. They are appearance, nature, entity, power, activity, causes, conditions, effects, consequences, and the unity of all phenomena.

The mutual possession of the Ten Worlds means that each of the Ten Worlds contains all ten within itself, bringing the total to 100 worlds. These 100 worlds are 100 different perspectives on life. Each possesses the Ten Factors of life, which brings the total up to 1,000. The mutual possession of the Ten Worlds is possible because the Ten Worlds all possess the Ten Factors in common. These Ten Factors are the ways in which one can analyze the common properties of life in all of the one hundred worlds.

Fundamentally, the Ten Factors show that the 100 worlds are all simply manifestations of the process of Dependent Origination, and therefore are empty of any fixed or independent existence.

The principle of the mutual possession of the Ten Worlds is based upon the fact that these worlds are not actually separate. They are simply different ways of experiencing life depending upon the prevailing cause and conditions that are in operation at any given moment. As such, they all flow into one another. It works like the weather – rainy days give way to cloudy days, which in turn become sunny days.

Each one also contains aspects of the others within itself. Even as there is a flow from one world to another, each world contains the others within itself. The lower worlds posses the higher worlds as ideals, whereas the higher worlds embrace the lower worlds through compassionate understanding based on personal experience.

The key point to remember, however, is that since we contain all of the Ten Worlds within ourselves, we also carry the world of Buddhahood. Therefore, we all have the capacity to bring out the world of the buddha from within as soon as we meet up with the right causes and conditions. The teaching of the mutual possession of the Ten Worlds is a very profound teaching, but even more important is the realization born from it that all beings are potential buddhas.
Lotus Seeds

The principle of the mutual possession of the Ten Worlds states that each of these Ten Worlds, or state’s of mind, contains all of the others within itself. They are not mutually exclusive. Despair, craving, impulsiveness, reasoning, pride, rapture, self­-discipline, insight, compassion, and awakening are all states of being that influence and even cause each other. For instance, we might experience great frustration driving to work through city traffic, but then become delighted the next moment when a favorite song comes on the radio, and listening to that song might lead to an insight about our own lives. This is just one example of an infinite number of combinations that we experience over the course of lifetimes, in the course of a single day, or even in a single moment. Though one or two states tend to predominate, they are all bound up in one another. The transformations between them are governed by the law of cause and effect.

The only real escape from the vicissitudes and uncertainty of the Six Worlds – hell-dwellers, hungry ghosts, animals, fighting demons, humanity and heaven – is to move into the Four Higher Worlds through the practice of the Buddha’s teachings. These four worlds are not actually different worlds or forms of rebirth like the first six. Instead, they indicate different ways of relating to and living within the first six. These Four Higher Worlds consist of the voice ­hearers, the privately awakened ones who take up the path of individual liberation, the bodhisattvas who compassionately strive for Lhe awakening of all beings, and the buddhas who have perfect, unsurpassed wisdom and infinite compassion.

The Four Higher Worlds, however, can also indicate levels of insight or compassionate activities that are associated with these various types of Buddhist practitioners. This broader interpretation of the Four Higher Worlds can be applied to anyone and everyone, even those who may not know about Buddhism or identify themselves as Buddhists.

The first six worlds – hell-dwellers, hungry ghosts, animals, fighting demons, humanity and heaven – are alike in that these states are driven by the Three Poisons of greed, hatred, and delusion to varying degrees. When in these states, we strive to make the world in which we live conform to our expectations and desires so that we can find security and lasting satisfaction. According to Buddhism, however, life is literally what we make of it. Despite our wishes, we will still only reap what we have sown. If we are kind and helpful to others, we will in turn discover that others are kind and helpful. If we mistreat others, we will find that others will mistreat us. This cycle is self-perpetuating: We are constantly making new causes based on our reactions to the effects of our previous causes in an effort to find a stable place of comfort and security. Unfortunately, there is no final resting place or lasting fulfillment within the Six Worlds because they are all in a constant state of changing and interacting with one another. One cannot even count on the heavenly states, because they are also impermanent and subject to change.

Of the Four Higher Worlds – voice­ hearers, privately awakened ones, bodhisattvas, and buddhas – the highest is the world of buddhas. This is the world viewed from the perspective of perfect, unsurpassed awakening. From this perspective, one can see that the world of birth and death is itself the pure land. The world of the buddhas also represents the Buddha-nature, which is our own capacity for perfect and unsurpassed awakening. This world transcends all the other states because it is free of their limitations and suffering, but is also inherent within them as their true nature, infinite and free of suffering.

Of the Four Higher Worlds – voice­hearers, privately awakened ones, bodhisattvas, and buddhas – the world of bodhisattvas is the world viewed as the world of compassionate endeavor, specifically the cultivation of the Six Perfections. Those who view the world in this way are not seeking to flee the world of birth and death, but stay within it in order to assist and teach others.

Of the Four Higher Worlds – voice­ hearers, privately awakened ones, bodhisattvas, and buddhas – the world of privately awakened ones is the world viewed from the perspective of Dependent Origination. Those who abide in this state of mind are able to realize the impermanence, suffering, and selflessness of the world for themselves through their own observations.