In previous posts, we have discussed the famous rule that when performing a permitted activity, one does not need to be concerned about it being accompanied by an unintended  forbidden activity, so long as that forbidden activity is not פסיק רישיה  (inevitable.)
For example, one is permitted to drag a bench along the ground even though it might make a ditch while being moved, seeing as this is not inevitable.
We have also shown that this leniency applies not only on shabbos, but also in other areas of halacha.
For example, a Nazir is permitted to scratch his beard even though some hair might fall out. This is because his intention is not to remove hair, but rather simply to scratch his beard, and the hair removal, though likely, is not inevitable.
We have also questioned whether the exemption of מתעסק, another category of unintended melacha, would apply to someone who intends to eat a fruit and unintentionally lands up swallowing an insect with it.
Though the rabbinic requirement to perform reasonable checks before eating fruit that are commonly infested is certainly not waived by such an exemption, in cases where checking sufficiently is impossible or involves extreme exertion, such an exemption could be very helpful, at least in combination with other reasons for leniency.
Even more helpful than this leniency which might mitigate the halachik concerns but would not permit the action לכתחילה,would be showing that we can apply the leniency of דבר שאין מתכוין  to this situation, seeing as such actions are permitted even לכתחילה.
Let us formulate it as follows:
A person wants to eat a raspberry. He has fulfilled the basic obligation to check it for insects, but has been told that they often hide in inaccessible places or camouflage so well that checking and removing them all is close to impossible, or would take so much time that it would simply not be viable.
The person intends to perform a permitted action- eating raspberries, which the Torah permitted.
There is a concern that while performing this permitted action, he might land up eating a bug, which is biblically prohibited (by multiple transgressions.)
It is presumably not inevitable that he will eat the bug, as there might not be a bug there, or it might have crawled or fallen out before he eats it.
 
(Some might argue this is actually a case of ספק פסיק רישיה  , seeing as if there is indeed a bug, one will definitely come to eat, and there is indeed a well-known debate whether ספק פסיק רישיה  has the same permitted status as דבר שאין מתכין  or is forbidden like פסיק רישיה .
However, even one argued that it was indeed פסיק רישיה , if would certainly be a פסיק רישיה דלא ניחא ליה  (inevitable but unintended result that one derives no benefit from at all, which according to some opinions is permitted and according to the more accepted stringent view is only rabbinically forbidden, making this a ספק פסיק רישיה דלא ניחיה ליה  about which we should be able to apply the rule of ספק דרבנן לקולא , or even a ספק ספיקא, given the views that both ספק פסיק רישיה  AND פסיק רישיה דלא ניחיה ליה  are permitted.  )
Surely we can apply the principle of דבר שאין מתכוין מותר and allow one to eat the fruit, seeing as one has no intention to eat the bug, if it is indeed there?
However, when one examines this more carefully, it is not a typical case of דבר שאין מתכוין, but more similar in some ways if anything to מתעסק.
In classic דבר שאין מתכוין, one intends to do a permitted action like dragging a bench and is concerned about a possible DIFFERENT secondary prohibited action, such as digging a groove.
In our case, one intends to perform the permitted action of eating a fruit and is concerned that one will come to apply the SAME action to a prohibited object, namely the bug.
(In Brisker terminology, in typical דבר שאין מתכוין, one intends to perform a מעשה של היתר and is concerned about a secondary מעשה של אסור.
In our case, it is the same מעשה one is concerned about, and the issue is the חפצא של אסור (prohibited object) on which the same מעשה will fall.)
In order to apply the leniency of דבר שאין מתכוין  which is already a חדוש (novel idea,) one would need to find a precedent for its application even when we are dealing with the same action, namely eating, an action one clearly intends to do, and the only lack of intent is for the secondary application of this same intended action to an unintended object, namely the bug.
This would still be different to מתעסק  in that the forbidden eating (the bug) would be secondary to the intended permitted eating (the fruit), not in place of it (intending to eat something kosher and eating something non-kosher [the issue of נהנה  aside])
I believe that we find exactly the precedent we are looking for on our daf!
Our daf discusses why it is permitted to perform a bris when there is a leprous lesion on the area about to be cut.
There is a biblical prohibition against cutting off such a lesion, and we have concluded that because there is also a positive command to avoid doing so, the normal rule of עשה דוחה לא תעשה  (a positive command pushes aside a negative one, cannot be applied to permit the bris.
Instead, the view of Rabbi Yoshiya is brought who learns this from a passuk.(the stressing of the word “בשר” – even if it has a lesion.)
The Gemara asks why this is necessary, seeing as it should be a case of דבר שאין מתכוין!
One has intention to cut off the ערלה (foreskin) in order to perform the mitzva of bris mila, and the cutting off of the lesion is only an unintended secondary action that accompanies it!
The Gemara answers that the permissive verse is still required seeing as this is an example of פסיק רישיה- an inevitable forbidden result.
We see that if not for the concern of פסיק רישיה (for example if the lesion was not on the site of bris but close to it,) this would indeed be a case of דבר שאין מתכוין.
Yet when we examine the case, we see that this is similar to the case of the fruit and the bug- one wishes to “cut” the ערלה  and the SAME action, namely “cutting”, is also likely to be unintentionally applied to a forbidden object, namely the צרעת  (lesion.)
If the rule of דבר שאין מתכוין did not apply to such a scenario, the question would not even begin, the Gemara would at least have given this as the reason it does not apply.
It indeed seems to follow from this Gemara that the leniency of דבר שאין מתכוין indeed applies also when the forbidden secondary action involves the same מעשה (act) as the permitted one!
It thus seems to follow that so long as one has fulfilled the rabbinic requirement to check commonly infested fruit before eating them, one should be permitted to eat it even if there is a real concern that some bugs might still remain.
This could even apply when checking is biblically required, such as when the majority of the species are known to be infested, so long as there is no פסיק רישיה.
If so, we can ask why there is even a rabbinic requirement to check fruit at all? Why not just rely on the leniency of דבר שאין מתכוין in the first place, something which no contemporary poseik I am aware of seems to suggest?
I believe that the answer lies in the way that the various Rishonim understands the prohibition of removing a leprous lesion.
The Rashba notes that the case on our daf does not appear like דבר שאין מתכוין- he actually says that it is more like מלאכה שאינה צריכא לגופא  seeing as one intends to perform  the action of cutting but not for the purpose of removing the lesion , rather in order to perform the מילה.
His classification of this as מלאכה שאינה צריכא לגופא  requires its own analysis but it is his answer that is most relevant here- he says that the prohibition from the Torah is not simply to cut the lesion but rather to intentionally purify himself by removing the lesion.
Seeing as he is cutting for the sake of the Mitzva of Milah and not with intention to purify himself, he has no intention for the prohibited action at all- there is a primary action of cutting off the ערלה  and a secondary unintended action of purifying himself- if this was not פסיק רישיה, it would thus be a classic case of דבר שאין מתכוין.
On the other hand, if there was indeed a prohibition of cutting off the lesion, and not of purifying oneself by so doing, this would not be דבר שאין מתכוין but rather מלאכה שאינה צריכה לגופא and thus prohibited.
This definition of the prohibition of removing a leprous lesion is  a huge chiddush, which the Rashba no doubt has his own proof for, and it is clear that according to this approach, this case can no longer serve as a precedent for our case with the fruit and the bugs.
What is also clear though, is that this is not the way most authorities define this prohibition- the Rambam, for example (Sefer haMitzvot 308 and Tumat Tzaraat 10/2) , and the Chinuch( Mitzva 584) define the prohibition simply as removing the signs of leprosy, ie the lesions.
Similarly, the Ritva brings 2 alternative answers to the Rashba’s question, which does not take this approach at all, and in fact suggests, in the name of the Ramban, that this is indeed a case of דבר שאין מתכוין, seeing as intention is to cut the milah, not the lesion, and the lesion is not all over the area of the מילה- almost exactly like our case with the fruit and the bug!
As such, defining our case as דבר שאין מתכוין seems to be subject to a dispute amongst Rishonim, and there is little wonder why Poskim are loathe to rely on it לכתחילה .
Indeed, the Rashba is amongst the most stringent of the Rishonim regarding the requirement to check even species that are not mostly infested but only have a מעוט המצוי  (common minority) of members infested, unlike Rashi, Tosfos, and possibly even the Rambam, who seem to hold that the requirement to check only applies where the majority of a species is infested (See my Hebrew Iyun for more on this.)
As common practise is to follow the Rashba, it seems that we cannot be lenient and  rely on דבר שאין מתכוין in the first place.
Once however, reasonable checks have been performed, the views that this is indeed דבר שאין מתכוין  certainly seems weighty enough to allow one to eat the fruit, even if there is still a concern of undetected bugs being present, even more so in conjunction with the many other reasons (for a different discussion) to be  lenient.
These posts are intended to raise issues and stimulate further research and discussion on contemporary topics related to the daf. They are not intended as psak halacha.