Natural Science Confronts Torah
These may you eat of all that are in the waters: whatsoever has fins and scales in the waters, in the seas, and in the rivers, them may you eat. And all that have not fins and scales in the seas, and in the rivers, of all that swarm in the waters, and of all the living creatures that are in the waters, they are a detestable thing unto you. And they shall be a detestable thing unto you; you shall not eat of their flesh, and their carcasses you shall have in detestation. Whatsoever has no fins nor scales in the waters, that is a detestable thing unto you. (Sefer VaYikra 11:9-12)
- Torah and science sometimes seem to contradict one another
There are various instances in which the position of the Torah seems to contradict observable data or conflict with the conclusions of science. For example, the Torah describes a universe that is thousands of years old. Science posits that the universe’s age should be measured in the billions of years. Another example is the health and medical directives in the Talmud. Some of these continue to conform to the views of contemporary science but other directives are apparently not in conformity with modern science. Parshat Shemini provides an important instance of an apparent conflict between observational data and a halachic assumption. This instance is interesting because the various proposed resolutions provide a survey of the common approaches to resolving such perceived conflicts.
- Fins and scales
The Torah explains that among aquatic creatures those which have fins and scales may be eaten. Those which do not have both of these characteristics are prohibited. The Talmud explains that it is assumed that a creature with scales will have fins. However, the reverse is not true. Some creatures with fins also have scales some do not.[1] The table below summarizes the assumptions of the Talmud:
| Observed characteristic | Assumed characteristic |
| Creature has scales | Creature has fins |
| Creature has fins | Creature may or may not have scales |
Is it true that every aquatic creature that has scales also has fins? The commentators, based on observation, questioned the validity of this assumption. They noted the existence of aquatic creatures that have scales but other appendages rather than fins. Their observations raised two questions. First, how can the observable facts be reconciled with the Talmud's principle that scales are always accompanied by fins? Second, what is the status of these creatures that have scales but not fins?
2. The paradox of scales but not fins
Essentially, these questions seem to suggest a contradiction between the Torah and natural science. Natural science had identified a species of aquatic creature that has scales but not fins. The Torah asserts that the presence of scales indicates that the creature has fins. What occurs when the principles of Torah are seemingly contradicted by natural science?
The commentators offer a number of solutions to these problems. Collectively, they provide a survey of the approaches to addressing apparent conflicts between the Torah and science. The following is a brief description of these responses based upon Aruch HaShulchan and Ma'adanai Yom Tov.
- Actually all aquatic creatures with scales have fins. The apparent exception is based upon an inaccurate observation. This creature must have fins which are somehow lost or shed when the creature is captured.[2]
- The halachic principle is not absolute. It is only a general assumption. Overwhelmingly, creatures with scales have fins. However, the halachic assumption does not preclude exceptions.[3]
- The halachic principle is derived from Sinai. It was correct at the time it was revealed to Moshe. However, biological life is continually developing and evolving. This means that the principle was true in the past but is no longer true.[4]
- The halachic principle is valid. However, it is not intended to apply to all aquatic creatures. It is limited to fish. It states that all fish with scales have fins. It does not posit that other aquatic creature other than fish possessing scales must also have fins.[5]
These answers represent radically different approaches to resolving the apparent conflict between natural science and halachah. The first response assumes that in such a conflict, the validity of the observation is suspect. It should be assumed that halachah is correct and an observational error has been made.
The third response makes the opposite assumption. It assumes that the observation is correct. Instead, the halachic principle – valid at its point of origin – is no longer valid. In other words, the Torah is correct in its assumptions regarding the natural world. However, that world can change and render halachah’s assumption invalid.
The second answer takes a path that is between the extremes. It assumes that both the halachic principle and the observed phenomenon are correct. However, it interprets the halachic principle in a manner that is both reasonable from the perspective of halachah and consistent with observation. The halachic principle is that generally aquatic creatures with scales have fins. Observation does not contradict this interpretation of the halachic principle.
The fourth and final approach is championed by Aruch HaShulchan. He rejects all of the other suggested solutions. He notes that a careful reading of Maimonides confirms that he maintains that the fin and scale criteria are not relevant to all aquatic creatures.[6] They are relevant only to fish. In other words, the permissibility of a fish is determined by the presence of fins and scales. Other aquatic creatures that have scales or fins are nonetheless prohibited. This answers both of the questions engendered by the aquatic creature that has scales but not fins. First, since it is clearly not a fish, the presence of scales does not render it permitted. Second, the rule of the Talmud that fins inevitably accompany scales remains intact. This assumption is only in regard to fish. It does not apply to other creatures.
The following table summarizes the classification system suggested by Aruch HaShulchan:
| Aquatic Creatures (a) | ||
| Fish (fins are characteristic of class) (b) | Other aquatic creatures (c) | |
| Fish with scales (Permitted) (d) | Fish without scales (Prohibited) (e) | |
This approach differs from the others. It does not assume that there is a conflict between observation and halachah. It assumes that halachah has its own classification system that is not necessarily bound to the classification system that a zoologist might develop. In the classification system of halachah, fish form a class (b) within the larger group that includes all aquatic creatures (a). A characteristic of the members of this class is that they have fins. A subclass has scales as well (d). Therefore, a fish with scales will certainly have fins. This is because fish with scales (d) are a subclass of fish (b) and fins are a basic and universal characteristic of the biological class that halachah identifies as fish. However a creature with fins – even if it is clearly a fish – may or may not be in the permitted subclass of fish that have scales (d or e).
An analogy will help clarify this approach to resolving the perceived conflict between halachah and observation. A craftsperson is fashioning an item of furniture to precise specifications. These specifications require that the legs of this item be five inches long and perfectly square. The craftsperson carefully measures and creates the required legs for the furniture item. He then enjoys a lunch with his close friend the mathematician. During their meal the craftsperson describes to his friend the beautiful item of furniture he has just created. His elaborate description includes the legs. The mathematician suddenly becomes agitated at the craftsman’s contention that he has created perfectly square legs. He insists that it is impossible that these legs are perfectly square.
Who is correct? The mathematician and the craftsperson is each correct from his unique perspective. The standard for “square” differs in their respective fields. For the craftsperson, the standard is empirical. If the leg is empirically square, then it meets the standard. For the mathematician, square is a geometric shape with strict, precise requirements. Almost square or empirically square is not square.
Halachah’s classification of biological diversity need not conform to the classifications of the zoologist. Like the craftsperson and mathematician, the zoologist and Torah scholar are both correct in their respective classification schemes. Appreciation of this concept will not resolve all of the apparent conflicts between science and Torah but it addresses many.
[1] Mesechet Niddah 51a.
[2] Rav Aharon HaLeyve Epstein, Aruch HaShulchan, Yoreh Dayah 83:5.
[3] Rav Aharon HaLeyve Epstein, Aruch HaShulchan, Yoreh Dayah 83:5.
[4] Rav Yom Tov Lippman Heller, Ma’adani Yom Tov, Glosses on Rabbaynu Asher, Mesechet Chullin 66b.
[5] Rav Aharon HaLeyve Epstein, Aruch HaShulchan, Yoreh Dayah 83:6.
[6] Rabbaynu Moshe ben Maimon (Rambam / Maimonides) Mishne Torah, Hilchot Ma’achalot Assurot 2:12.