In general, Medhātithi’s commentary systematizes the MDh. In the case of action and intention, he does his best to iron away seeming incongruities by explaining that intentional actions are liable to more blame than unintentional ones, which he accomplishes by adding the needed adverbs or adjective to the wording of MDh (e.g., in his commentary on 9.242 (on intentional vs unintentional crimes), 11.56, 11.77 (on the intentional vs unintentional killing of Brāhmaṇas), 11.125, 11.209 (on deciding expiations when no one is explicitly prescribed)). Accordingly, Medhātithi explains away the “unintentionally” in MDh 11.127, because the strength of the penalty implies that the action was performed intentionally.

As often the case in his commentary, Medhātithi derives his philosophical framework of reference from the deontic teachings of the philosophical school of Mīmāṃsā. For instance, he does not add his own definition of “action” and “intention”, but presupposes the Mīmāṃsā understanding of these concepts.
The speculation on action starts for Mīmāṃsā philosophers by considering the paradigmatic case of complex ritual actions. This means that they consider first and foremost actions spanning over a long period of time (hours or even days) and that cannot be easily explained as the result of ephemeral desires, but rather require what Alfred Mele calls “distal intentions” (intentions about the non-immediate future, see Mele 2006). Nonetheless, they all agree about the pivotal role of desire in action and, in this sense, ground each complex action ultimately in a “primitive” desire (i.e., a desire for something independently desirable, and not desirable for the sake of something else). Typical examples for primitive desires are desires for sons, rain, cattle, happiness, whereas desiring to know the meaning of a certain passage is considered subservient to some other desire, which has led one to read the corresponding text.
Accordingly, Mīmāṃsā authors distinguish between main actions and the activities they are composed of; one’s intention relates to the main action, whereas the intermediate activities are needed sub-steps, but are not independently intended. Therefore, different rules apply to the two sets. This bipartition is taken for granted also in the MDh and by Medhātithi. For instance, MDh 11.11–12 discuss the case of a main action (a sacrifice) being interrupted for want of an ingredient needed for an intermediate activity. Since the main action needs to be completed, one is allowed to complete it even by appropriating a single ingredient in a way which would not be normally allowed (taking it away from someone who does not need it). In other words, the need to complete the main action creates a situation of necessity that permits one to act in a sub-ideal way.
Intention is not dealt separately from blame in the Dharmasūtras nor in the MDh. However, Medhātithi is himself an insightful thinker and often takes up small clues in the MDh to open up a deeper discussion, and this happens in the case of his discussion of intention. Specifically, Medhātithi adds a second axis to the one examined above concerning intentions, prohibitions, and expiations, namely that of intention (saṅkalpa) and motivation. Near the beginning of the MDh, the elements underlying one’s observance of law is briefly outlined, including intention and desire:

To be motivated by desire is not commended, but it is impossible here to be free from desire; for it is desire that prompts vedic study and the performance of vedic rites.
Intention is the root of desire; intention is the wellspring of sacrifices; and intention triggers every religious observance and every rule of restraint—so the tradition declares. Nowhere in this world do we see any activity done by a man free from desire; for whatever at all that a man may do, it is the work of someone who desired it.
By engaging in them properly, a man attains the world of the immortals and, in this world, obtains all his desires just as he intended.

In this passage, Manu asserts a few things. First, he asserts that both engaging in activity and refraining from particular activities are “triggered” by intention (“intention triggers every religious observance and every rule of restraint”). The terminology suggests that Medhātithi is thinking of activities that would have otherwise taken place, and which demand effort on one’s side to be avoided (such as lightning a cigarette as the first thing in the morning for a passionate smoker). In other words, intention triggers one to change the present inertia, be it by undertaking something or refraining from acting inertially.
Second, he asserts—perhaps counter to intuitive notions—that it is intention that comes before and necessitates desire (“intention is the root of desire”). Third, he asserts that desire is a requirement for acting in the world (“Nowhere in this world do we see any activity done by a man free from desire; for whatever at all that a man may do, it is the work of someone who desired it”).
In his commentary, Medhātithi’s develops the ideas in this passage. Specifically, Medhātithi outlines the concept of intention and the required elements for action. Medhātithi introduces the topic of his commentary by first quoting a portion of Manu’s above passage:
Intention is the root of desire; intention is the wellspring of sacrifices; and intention triggers every religious observance and every rule of restraint—so the tradition declares.

Medhātithi then goes on to further explicate a view of how intention relates to desire and action, responding to various objections:

And therefore, he (Manu) spells out what has been said, namely that without a desire the nature of a sacrifice is not carried out. An intention is the root of sacrifices and similar actions, and of desire. A person who desires to perform a sacrifice or a similar action necessarily forms an intention. And when an intention is being formed, it is necessarily the case that a desire is also brought close as caused by it, even if this (desire) is itself not wished. Just like when a person aiming at cooking burns [wood-logs] also smoke is produced, even if unwished, insofar as it is caused by that same cause. In this regard, it is impossible that a sacrifice or a similar action is performed, if desire does not occur.

[Obj.:] Then, what is this intention, which you say to be the root of all actions?

[R:] It is the appearance (sandarśana) of consciousness (cetas), after which desiring (prārthanā) and ascertaining, one after the other, occur. In fact, these mental activities (vyāpāra) attain the role of root for the undertaking of all actions. For, it is not the case that material activities are possible without them. To elaborate: First of all, one ascertains the nature of a given thing, e.g. “This thing produces this effect”. This cognition is here called intention. Thereafter, desiring (prārthanā), i.e., will (icchā) occurs. This is desire (kāma). Once one has the will “How will I realise that (thing) through that (action)?”, one ascertains “I will do it”. This is the ascertaining. Thereafter, one undertakes an action with regard to an external activity which is the instrument to realise [one’s goal]. For instance, a person who wants to eat something first observes the action of eating [by someone else], then wishes “May I eat!”, then ascertains “I will abandon all other activities and eat!”. Then, he tells to the action, the cause, the place and the eligible person: ‘Come together, prepare (sajjīkṛ-) a succulent [food]’.

[Obj.:] But if this is the case, sacrifice and similar actions do not occur just because of an intention. Rather, they occur because of intention, desire and ascertaining. Thus, why does Manu say “sacrifices originate out of intentions”?

[R:] There is no flaw, since the intention is the original cause. For this very reason, he (Manu) will later say that one never sees any action by a person who does not desire anything.

These passages favour a plain reading of the claim in Manu whereby intentions are the root cause of engagement in sacrifices and other actions. At its core, the understanding of intention furthered here appears to be a basic consciousness of how certain acts relate to certain ends. While intentions have an initiatory role, desire and ascertainment necessarily follow. This approach is distinct from cognitivism (as defined by Sarah Paul), insofar as intentions are volitions and not identical with the corresponding beliefs.
In which sense can intention be the cause of desire and not the opposite? Is not it the case that we first experience appetites, then move on to form the intention to satisfy them and then perform the relevant sequence of acts? Let us start with Medhātithi’s starting point, namely that of complex actions, such as sacrifices, that extend through time. In their case, the claim that a basic appetite is what causes one to act, appears less plausible, because appetites are ephemeral and cannot sustain a longer cycle of activities. Accordingly, Medhātithi’s account makes perfect sense when it comes to actions that are performed not because of a basic appetite, but because of a conscious decision, but can it apply also to other kinds of actions?

While focus is placed in these passages on sacrificial and “similar actions”, which indicates a series of complex actions aimed at a particular result, Medhātithi makes it clear that the mental activities of intending, desiring, and ascertaining are the “root for the undertaking of all actions”. This sets up a fairly robust picture of action whereby actors hold in their minds a consciousness of how they understand their movements to interact with the world, which will result in a particular and desired end. In this sense, the psychological sequence Medhātithi sketched above could be a depiction of the phenomenological process through which a certain level of consciousness is a preliminary requirement for the process to be started, but cognition and appetite are also needed. The emphasis on phenomenology is due to the fact that it is hard to make sense of the statement that intentions generate desires (could one say “I intend to have dinner, therefore I am starting to feel hungry”?), but it makes sense that one only becomes aware of desire after having conceived the corresponding intention (“I intend to have dinner and realize that I am in fact hungry”). If taken to its extreme consequences, this would imply that there are no genuine conflicts between intentions and desires, because desires become available to one’s consciousness only once one has intended to do something. If desires are not directly responsible for our actions, how can Medhātithi explain episodes that are often ascribed to them, e.g. in case of what Euro-American philosophers call the “weakness of the will”? For instance, how could he explain the case of one failing to dress up to go to an opera even though they had previously formed the intention to go? Medhātithi could deal with is as a conflict among intentions, not among different causal factors (the intention to go and the desire to stay home) determining one’s actions. Alternatively, he could mention how inertial states take stronger intentions to be resisted and discuss such examples as based on a conflict between an intention and a hard-to-break inertial state. He could argue that it would be hard to dress up even independently of an active desire to stay home (thus proving that the problem is not due to a conflict between intentions and desires), because dressing up (like any act) involves effort, and all efforts are only undertaken if one sees that a bigger advantage will come of out them.

What do you think? Given Medhātithi’s premisses, does my extension of his thought to the above case make sense?