Continuity theory proposes that individuals strive to maintain a sense of continuity between their past and present lives, and that meaningful aging involves adapting to new circumstances while preserving core values and beliefs.

Activity theory posits that older adults who remain active and engaged in various social roles and activities are more likely to experience a sense of purpose and well-being.

Disengagement theory proposes that older adults gradually withdraw from social roles and activities as they age, and that this withdrawal can be beneficial for both the individual and society.

Socioemotional selectivity theory proposes that older adults prioritize deep and meaningful relationships over the quantity of social contacts, and that these relationships contribute to their sense of well-being.

Spiritual well-being theory proposes that spirituality and religion can provide older adults with a sense of purpose, meaning, and comfort, and that these factors contribute to their overall well-being.

The theory of successful aging proposes that a meaningful old age involves low levels of physical and mental impairment, active engagement in social and productive activities, and a sense of life satisfaction.

Personal growth theory proposes that older adults can achieve a meaningful old age by continuing to learn, grow, and develop throughout their lives.

The theory of reminiscence proposes that older adults can find meaning and purpose in their lives by reflecting on and sharing their past experiences.

Social support theory proposes that older adults who have strong social support networks are more likely to experience a sense of well-being and meaning in their lives.

The theory of environmental mastery proposes that older adults can achieve a meaningful old age by adapting their environment to meet their changing needs and abilities.

Legacy theory proposes that older adults can achieve a meaningful old age by focusing on their legacy and the impact they have had on others.

The theory of gerotranscendence proposes that older adults can achieve a meaningful old age by transcending the limitations of the physical body and ego, and by embracing a more spiritual and interconnected view of life.

Intergenerational theory proposes that older adults can achieve a meaningful old age by engaging in positive and meaningful relationships with younger generations.

The theory of positive aging proposes that older adults can achieve a meaningful old age by adopting a positive and optimistic outlook on life, and by focusing on their strengths and abilities.

Personal growth theory proposes that older adults can achieve a meaningful old age by continuing to learn, grow, and develop throughout their lives.