Kalpa means projection, forming (from the Sanskrit root kḷp), vi means apart, away from. This is interesting. Vikalpa is thus the fragmentation of unity into thousands of mental shards. Welcome to the hall of mirrors of the mind.

Vikalpa thus means mental division, and this results in misinterpretation of perception.

In individual ignorance, truth is covered, and a scattered world of thought is projected. Whoever projects a uniform, self-assured world of thought, lives in a correspondingly quiet world. It is the projection of a whole range of choices and doubts, which give a fragmented worldview. Vikalpa thus stands for the fragmentation, absent-mindedness, doubt and mobility of the mind.

Such division in the mind leads to seeing many options for action. Options that ostensibly make use of the free will to make a choice. The feeling of free will is caused by the ignorant assumption that there is an I (ahaṅkāra) that would have to make choices autonomously. This causes doubt and stress of choice. While an individual is just a link in the cosmic engine. And the sage always knows what has to be done (saṅkalpa) because his or her intellect is impregnated with īśvara and the knowledge that īśvara decides and does anyway, and you better leave it that way, because otherwise you will make karma. “Whatever comes to me, I do”.

The way to get into this state of mind karma yoga. One, adopt an attitude that makes me contribute to the whole in love. Two, accept what comes back from the field. In short, surrender.

The two terms saṅkalpa and vikalpa are usually used together to refer to a thinking activity in which the mind tries to work towards a certain decisiveness (saṅkalpa). The thinker thinks he knows what needs to be done. But then doubts can still arise. Suddenly, other options (vikalpas) are created by the mind, deliberating and weighing between the different options for action.

The doubt is of course between vikalpas, because a saṅkalpa would not be a saṅkalpa if it is part of the doubt between left and right. In the case of saṅkalpa, it has already been decided.

The knowing sage has hardly any vikalpas, for he lives with self-knowledge as saṅkalpa (decisive conviction).

It is the challenge of the intellect to mature and to have a feeler for īśvara. Then issues are neatly solved, and people know flawlessly whether they can do something, or can do nothing, whether they know something, or don't know something, or choose the best choice between the options that manas offers. Buddhi thus gives a blow to the doubts of vikalpa, and gives a clear assessment of the situation and clarity about what should be done.

Is doubt bad then? Not at all. Nothing is there without a reason. The whole plan is designed in such a way that there are ways out. Hence the doubt function vikalpa. Suppose I have a limiting belief (saṅkalpa) that is all-determining in my life. For example: I have to live symbiotically with my partner, in order to be connected (I can better see that I am symbiotically connected with Bhagavān). Or I need alcohol or drugs to not feel bad. Suppose I had no doubts. Then I wouldn't have a gnawing feeling that there are other, better, sustainable solutions to be happy.

In the same way: Suppose I am chasing security of existence (artha), or I am chasing pleasures, leisure activities and distraction from the emptiness and dullness of my experience (kāma), or I must and will take care of informal care or improve others and the world (dharma), but I always come home from a rude awakening, and feel cheated in my happiness etc. Then it is the built-in doubt (!) that tells me that maybe I should start thinking differently, that ignorance is the problem and knowledge is the solution to freedom (mokṣa). This is also sometimes expressed by people, for example in their midlife crisis: “This can't be it, can it?” Doubt can make a person a seeker of truth.

Conclusion: With someone who knows that he is the self, vikalpa plays a much less important role. He or she lives in saṅkalpa, as it were, because she or he (the person) allows himself (the person) to be lived by īśvara, and thus always spontaneously and mindfully does what needs to be done. And it doesn't really matter to him or her what happens. Hence surrender.

As consciousness, such a sage does nothing himself and knows: Īśvara apparently decides what happens. That sage likes to surrender his apparent life to an apparent god, who is 100% professional in living a good life. So why not let god run life and enjoy the show? If you let the long arm of īśvara reach into all the details of your life, you will be rocked forever. That is easiest if I call myself free consciousness, and thus view reality, without hassle.