Maharajji answers questions in Śrī Guru Darśanam, p 20

Question: Can you explain how Bhagavān is devoid of different types of bhedas?

Answer: Bhagavān has potencies; and between śakti (potency) and śaktimāna (who possesses the potency), there is no bheda (difference) or abheda (non-difference). He is the only one who exists, and He is the possessor of the potencies. You cannot say that there is absolute bheda (difference) between Him and His potencies, nor can you say that there is abheda (difference). In reality, there is neither bheda nor abheda. It is unavoidable to consider that Bhagavān is simultaneously bheda and abheda, one and different, because nothing else can explain reality properly.

Question: So, all the other Vaiṣṇava philosophies then are incomplete in their conception?
Answer: The other philosophies try to explain this difference and non-difference by using different words. If you analyze them closely, then you will see that each one of them has to accept both difference and non-difference simultaneously.

For example, take Viśiṣtadvaiṭa, qualified monism. The word viśiṣṭa means qualified. So, qualified with what? Then you have to say it is qualified with māyā-śakti and jīva-śakti. Then the question arises, with what relationship is it qualified? Basically, the relations are saṁyoga sambandha, which means physical contact, and samavāya sambandha, which means inherent contact. Both of these are impossible. Saṁyoga is between two separate objects. Then māyā or jīva could not be His own potency. And if you take samavāya as the relation, then it becomes a permanent characteristic; so all the defects of the material world would be inherent in Bhagavān. Therefore, a separate relation called apṛthaka-siddhi is accepted.

Similarly, when you say bhedābheda, then it is like Nṛsimha – one part is like a lion and the other is like a human being. Reality is not divided into two. Therefore it is qualified by the word svābhāvika or natural. But by calling it natural, the problem of the limitations of māyā being reflected in the Absolute is unavoidable.

Or, if you say Śuddhādvaita, the pure monism of Vallabhācarya, then what is the impurity, which is not found in Advaita? You give a qualification to distinguish it from something. So if the Absolute is Śuddhadvaita, then what is aśuddhādvaita?

The point is that Bhagavān is acintya, or trans-rational, which means śāstraika-gamyam. He can be known only from scriptures and not by logic alone. It is like the heat energy of fire. Heat exists in the fire; it is its own svarūpa. It is neither beyond its own svarūpa nor can it exist independently. In this sense, there is oneness; yet heat and fire are not absolutely one. Similarly Bhagavān has potency, and thus there is variety, as we can all perceive the variety; yet the Absolute has to be one. This can be known only from śāstra. So basically the explanations of all other philosophies are based on logic, but that does not work, even though they also give pramāṇa, or authority of śāstra. No one, however, can deny the acintya concept. All the philosophies have accepted the inconceivable feature of the Absolute.

Monism also cannot be established, because it is called advaita. Advaita means na dvaita iti advaita- that which is not dvaita (dual). And “not” can have six different meanings:

1. It is similar to dvaita.
2. There is non-existence of dvaita.
3. There is a little of dvaita.
4. It is different from dvaita (it could be one or three or four).
5. It is not a very good dvaita.
6. It is contrary to dvaita.

None of these can prove monism. Even if you say advaita is that which is not two, or dvaita, which means complete non-existence of two, you still cannot say “not two” unless “two” exists. You cannot deny the existence of something unless the object exists. If it never existed, then there is no sense in saying, “It does not exist”. Whenever you say that something does not exist, it means that it exists somewhere in the past, present or future. If it has never existed, does not exist now, anywhere, and will never exist in the future, then you can never say, “It does not exist”. So to deny the existence of something, you have to first accept its existence. Therefore there is no possibility of advaita, unless dvaita is accepted. And if advaita is absolute, then dvaita must also be absolute.

Similarly all the other meanings of advaita, such as, “not too much of dvaita,” or “separate from dvaita”, or “not a very good dvaita (aprāśatya)” – all these meanings do not prove monism.